Move Diskstream ownership to Track, so that Session no longer holds lists of Diskstre...
[ardour.git] / gtk2_ardour / editor_ops.cc
index e61c8d6abe20dfbc3c6939c74b38bc0f44a1413a..7f3aa7f7a84347feef185d86eb0fb86b05e562c7 100644 (file)
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2000-2004 Paul Davis 
+    Copyright (C) 2000-2004 Paul Davis
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
 #include "pbd/pthread_utils.h"
 #include "pbd/memento_command.h"
 #include "pbd/whitespace.h"
+#include "pbd/stateful_diff_command.h"
 
 #include <gtkmm2ext/utils.h>
 #include <gtkmm2ext/choice.h>
-#include <gtkmm2ext/window_title.h>
 #include <gtkmm2ext/popup.h>
 
 #include "ardour/audioengine.h"
@@ -45,7 +45,6 @@
 #include "ardour/audio_diskstream.h"
 #include "ardour/utils.h"
 #include "ardour/location.h"
-#include "ardour/named_selection.h"
 #include "ardour/audio_track.h"
 #include "ardour/audioplaylist.h"
 #include "ardour/region_factory.h"
@@ -55,6 +54,7 @@
 #include "ardour/dB.h"
 #include "ardour/quantize.h"
 #include "ardour/strip_silence.h"
+#include "ardour/route_group.h"
 
 #include "ardour_ui.h"
 #include "editor.h"
 #include "utils.h"
 #include "editor_drag.h"
 #include "strip_silence_dialog.h"
+#include "editor_routes.h"
+#include "editor_regions.h"
+#include "quantize_dialog.h"
+#include "interthread_progress_window.h"
 
 #include "i18n.h"
 
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
-using namespace sigc;
 using namespace Gtk;
 using namespace Gtkmm2ext;
 using namespace Editing;
+using Gtkmm2ext::Keyboard;
 
 /***********************************************************************
   Editor operations
@@ -94,34 +98,19 @@ using namespace Editing;
 void
 Editor::undo (uint32_t n)
 {
-       if (session) {
-               session->undo (n);
+       if (_session) {
+               _session->undo (n);
        }
 }
 
 void
 Editor::redo (uint32_t n)
 {
-       if (session) {
-               session->redo (n);
+       if (_session) {
+               _session->redo (n);
        }
 }
 
-void
-Editor::split_region ()
-{
-       split_region_at (get_preferred_edit_position());
-}
-
-void
-Editor::split_region_at (nframes64_t where)
-{
-       RegionSelection rs;
-
-       get_regions_for_action (rs);
-       split_regions_at (where, selection->regions);
-}
-
 void
 Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
 {
@@ -137,7 +126,7 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
        // region boundaries, don't pay attention to them
 
        if (regions.size() == 1) {
-               switch (snap_type) {
+               switch (_snap_type) {
                case SnapToRegionStart:
                case SnapToRegionSync:
                case SnapToRegionEnd:
@@ -156,7 +145,7 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
                /* XXX this test needs to be more complicated, to make sure we really
                   have something to split.
                */
-               
+
                if (!(*a)->region()->covers (where)) {
                        ++a;
                        continue;
@@ -167,10 +156,16 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
 
                boost::shared_ptr<Playlist> pl = (*a)->region()->playlist();
 
-               if (! pl->frozen()) {
+                if (!pl) {
+                        cerr << "region " << (*a)->region()->name() << " has no playlist!\n";
+                        a = tmp;
+                        continue;
+                }
+
+               if (!pl->frozen()) {
                        /* we haven't seen this playlist before */
 
-                       /* remember used playlists so we can thaw them later */ 
+                       /* remember used playlists so we can thaw them later */
                        used_playlists.push_back(pl);
                        pl->freeze();
                }
@@ -179,12 +174,11 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
                if (arv) {
                        _new_regionviews_show_envelope = arv->envelope_visible();
                }
-               
+
                if (pl) {
-                       XMLNode &before = pl->get_state();
+                        pl->clear_history ();
                        pl->split_region ((*a)->region(), where);
-                       XMLNode &after = pl->get_state();
-                       session->add_command(new MementoCommand<Playlist>(*pl, &before, &after));
+                       _session->add_command (new StatefulDiffCommand (pl));
                }
 
                a = tmp;
@@ -195,27 +189,27 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
                (*i)->thaw();
                used_playlists.pop_front();
        }
-       
+
        commit_reversible_command ();
        _new_regionviews_show_envelope = false;
 }
 
 boost::shared_ptr<Region>
-Editor::select_region_for_operation (int dir, TimeAxisView **tv)
+Editor::select_region_for_operation (int /*dir*/, TimeAxisView **tv)
 {
        RegionView* rv;
        boost::shared_ptr<Region> region;
        nframes64_t start = 0;
 
        if (selection->time.start () == selection->time.end_frame ()) {
-               
+
                /* no current selection-> is there a selected regionview? */
 
                if (selection->regions.empty()) {
                        return region;
                }
 
-       } 
+       }
 
        if (!selection->regions.empty()) {
 
@@ -231,18 +225,18 @@ Editor::select_region_for_operation (int dir, TimeAxisView **tv)
 
                if ((rtv = dynamic_cast<RouteTimeAxisView*> (*tv)) != 0) {
                        boost::shared_ptr<Playlist> pl;
-                       
+
                        if ((pl = rtv->playlist()) == 0) {
                                return region;
                        }
-                       
+
                        region = pl->top_region_at (start);
                }
-       } 
-       
+       }
+
        return region;
 }
-       
+
 void
 Editor::extend_selection_to_end_of_region (bool next)
 {
@@ -260,14 +254,8 @@ Editor::extend_selection_to_end_of_region (bool next)
                start = selection->time.start ();
        }
 
-       /* Try to leave the selection with the same route if possible */
-
-       if ((tv = selection->time.track) == 0) {
-               return;
-       }
-
        begin_reversible_command (_("extend selection"));
-       selection->set (tv, start, region->position() + region->length());
+       selection->set (start, region->position() + region->length());
        commit_reversible_command ();
 }
 
@@ -289,13 +277,9 @@ Editor::extend_selection_to_start_of_region (bool previous)
        }
 
        /* Try to leave the selection with the same route if possible */
-       
-       if ((tv = selection->time.track) == 0) {
-               return;
-       }
 
        begin_reversible_command (_("extend selection"));
-       selection->set (tv, region->position(), end);
+       selection->set (region->position(), end);
        commit_reversible_command ();
 }
 
@@ -327,48 +311,47 @@ Editor::nudge_forward (bool next, bool force_playhead)
 {
        nframes64_t distance;
        nframes64_t next_distance;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
-       if (!session) return;
-       
+       if (!_session) return;
+
        if (!force_playhead && !rs.empty()) {
 
                begin_reversible_command (_("nudge regions forward"));
 
                for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                        boost::shared_ptr<Region> r ((*i)->region());
-                       
+
                        distance = get_nudge_distance (r->position(), next_distance);
 
                        if (next) {
                                distance = next_distance;
                        }
 
-                        XMLNode &before = r->playlist()->get_state();
+                        r->clear_history ();
                        r->set_position (r->position() + distance, this);
-                        XMLNode &after = r->playlist()->get_state();
-                       session->add_command (new MementoCommand<Playlist>(*(r->playlist()), &before, &after));
+                       _session->add_command (new StatefulDiffCommand (r));
                }
 
                commit_reversible_command ();
 
-               
+
        } else if (!force_playhead && !selection->markers.empty()) {
 
                bool is_start;
 
                begin_reversible_command (_("nudge location forward"));
-               
+
                for (MarkerSelection::iterator i = selection->markers.begin(); i != selection->markers.end(); ++i) {
-                       
+
                        Location* loc = find_location_from_marker ((*i), is_start);
-                       
+
                        if (loc) {
-                               
+
                                XMLNode& before (loc->get_state());
-                               
+
                                if (is_start) {
                                        distance = get_nudge_distance (loc->start(), next_distance);
                                        if (next) {
@@ -391,29 +374,29 @@ Editor::nudge_forward (bool next, bool force_playhead)
                                        }
                                }
                                XMLNode& after (loc->get_state());
-                               session->add_command (new MementoCommand<Location>(*loc, &before, &after));
+                               _session->add_command (new MementoCommand<Location>(*loc, &before, &after));
                        }
                }
-               
+
                commit_reversible_command ();
-               
+
        } else {
                distance = get_nudge_distance (playhead_cursor->current_frame, next_distance);
-               session->request_locate (playhead_cursor->current_frame + distance);
+               _session->request_locate (playhead_cursor->current_frame + distance);
        }
 }
-               
+
 void
 Editor::nudge_backward (bool next, bool force_playhead)
 {
        nframes64_t distance;
        nframes64_t next_distance;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
-       if (!session) return;
-       
+       if (!_session) return;
+
        if (!force_playhead && !rs.empty()) {
 
                begin_reversible_command (_("nudge regions backward"));
@@ -422,20 +405,19 @@ Editor::nudge_backward (bool next, bool force_playhead)
                        boost::shared_ptr<Region> r ((*i)->region());
 
                        distance = get_nudge_distance (r->position(), next_distance);
-                       
+
                        if (next) {
                                distance = next_distance;
                        }
+                        
+                        r->clear_history ();
 
-                        XMLNode &before = r->playlist()->get_state();
-                       
                        if (r->position() > distance) {
                                r->set_position (r->position() - distance, this);
                        } else {
                                r->set_position (0, this);
                        }
-                        XMLNode &after = r->playlist()->get_state();
-                       session->add_command(new MementoCommand<Playlist>(*(r->playlist()), &before, &after));
+                       _session->add_command (new StatefulDiffCommand (r));
                }
 
                commit_reversible_command ();
@@ -449,11 +431,11 @@ Editor::nudge_backward (bool next, bool force_playhead)
                for (MarkerSelection::iterator i = selection->markers.begin(); i != selection->markers.end(); ++i) {
 
                        Location* loc = find_location_from_marker ((*i), is_start);
-                       
+
                        if (loc) {
-                               
+
                                XMLNode& before (loc->get_state());
-                       
+
                                if (is_start) {
                                        distance = get_nudge_distance (loc->start(), next_distance);
                                        if (next) {
@@ -466,33 +448,33 @@ Editor::nudge_backward (bool next, bool force_playhead)
                                        }
                                } else {
                                        distance = get_nudge_distance (loc->end(), next_distance);
-                                       
+
                                        if (next) {
                                                distance = next_distance;
                                        }
-                                       
+
                                        if (distance < loc->end() - loc->length()) {
                                                loc->set_end (loc->end() - distance);
                                        } else {
                                                loc->set_end (loc->length());
                                        }
                                }
-                               
+
                                XMLNode& after (loc->get_state());
-                               session->add_command (new MementoCommand<Location>(*loc, &before, &after));
+                               _session->add_command (new MementoCommand<Location>(*loc, &before, &after));
                        }
                }
 
                commit_reversible_command ();
-                       
+
        } else {
 
                distance = get_nudge_distance (playhead_cursor->current_frame, next_distance);
 
                if (playhead_cursor->current_frame > distance) {
-                       session->request_locate (playhead_cursor->current_frame - distance);
+                       _session->request_locate (playhead_cursor->current_frame - distance);
                } else {
-                       session->goto_start();
+                       _session->goto_start();
                }
        }
 }
@@ -501,60 +483,58 @@ void
 Editor::nudge_forward_capture_offset ()
 {
        nframes64_t distance;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
-       if (!session) return;
-       
+       if (!_session) return;
+
        if (!rs.empty()) {
 
                begin_reversible_command (_("nudge forward"));
 
-               distance = session->worst_output_latency();
+               distance = _session->worst_output_latency();
 
                for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                        boost::shared_ptr<Region> r ((*i)->region());
-                       
-                       XMLNode &before = r->playlist()->get_state();
+
+                        r->clear_history ();
                        r->set_position (r->position() + distance, this);
-                       XMLNode &after = r->playlist()->get_state();
-                       session->add_command(new MementoCommand<Playlist>(*(r->playlist()), &before, &after));
+                       _session->add_command(new StatefulDiffCommand (r));
                }
 
                commit_reversible_command ();
 
-       } 
+       }
 }
-               
+
 void
 Editor::nudge_backward_capture_offset ()
 {
        nframes64_t distance;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
-       if (!session) return;
-       
+       if (!_session) return;
+
        if (!rs.empty()) {
 
                begin_reversible_command (_("nudge forward"));
 
-               distance = session->worst_output_latency();
+               distance = _session->worst_output_latency();
 
                for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                        boost::shared_ptr<Region> r ((*i)->region());
 
-                        XMLNode &before = r->playlist()->get_state();
-                       
+                        r->clear_history ();
+
                        if (r->position() > distance) {
                                r->set_position (r->position() - distance, this);
                        } else {
                                r->set_position (0, this);
                        }
-                        XMLNode &after = r->playlist()->get_state();
-                       session->add_command(new MementoCommand<Playlist>(*(r->playlist()), &before, &after));
+                       _session->add_command(new StatefulDiffCommand (r));
                }
 
                commit_reversible_command ();
@@ -566,14 +546,14 @@ Editor::nudge_backward_capture_offset ()
 void
 Editor::move_to_start ()
 {
-       session->goto_start ();
+       _session->goto_start ();
 }
 
 void
 Editor::move_to_end ()
 {
 
-       session->request_locate (session->current_end_frame());
+       _session->request_locate (_session->current_end_frame());
 }
 
 void
@@ -587,30 +567,30 @@ Editor::build_region_boundary_cache ()
 
        region_boundary_cache.clear ();
 
-       if (session == 0) {
+       if (_session == 0) {
                return;
        }
-       
-       switch (snap_type) {
+
+       switch (_snap_type) {
        case SnapToRegionStart:
                interesting_points.push_back (Start);
                break;
        case SnapToRegionEnd:
                interesting_points.push_back (End);
-               break;  
+               break;
        case SnapToRegionSync:
                interesting_points.push_back (SyncPoint);
-               break;  
+               break;
        case SnapToRegionBoundary:
                interesting_points.push_back (Start);
                interesting_points.push_back (End);
-               break;  
+               break;
        default:
-               fatal << string_compose (_("build_region_boundary_cache called with snap_type = %1"), snap_type) << endmsg;
+               fatal << string_compose (_("build_region_boundary_cache called with snap_type = %1"), _snap_type) << endmsg;
                /*NOTREACHED*/
                return;
        }
-       
+
        TimeAxisView *ontrack = 0;
        TrackViewList tlist;
 
@@ -620,7 +600,7 @@ Editor::build_region_boundary_cache ()
                tlist = track_views;
        }
 
-       while (pos < session->current_end_frame() && !at_end) {
+       while (pos < _session->current_end_frame() && !at_end) {
 
                nframes64_t rpos;
                nframes64_t lpos = max_frames;
@@ -642,7 +622,7 @@ Editor::build_region_boundary_cache ()
 
                        case End:
                                rpos = r->last_frame();
-                               break;  
+                               break;
 
                        case SyncPoint:
                                rpos = r->sync_position ();
@@ -652,16 +632,16 @@ Editor::build_region_boundary_cache ()
                        default:
                                break;
                        }
-                       
+
                        float speed = 1.0f;
                        RouteTimeAxisView *rtav;
-                       
+
                        if (ontrack != 0 && (rtav = dynamic_cast<RouteTimeAxisView*>(ontrack)) != 0 ) {
-                               if (rtav->get_diskstream() != 0) {
-                                       speed = rtav->get_diskstream()->speed();
+                               if (rtav->track() != 0) {
+                                       speed = rtav->track()->speed();
                                }
                        }
-                       
+
                        rpos = track_frame_to_session_frame (rpos, speed);
 
                        if (rpos < lpos) {
@@ -672,8 +652,8 @@ Editor::build_region_boundary_cache ()
                           to sort later.
                        */
 
-                       vector<nframes64_t>::iterator ri; 
-                       
+                       vector<nframes64_t>::iterator ri;
+
                        for (ri = region_boundary_cache.begin(); ri != region_boundary_cache.end(); ++ri) {
                                if (*ri == rpos) {
                                        break;
@@ -709,11 +689,11 @@ Editor::find_next_region (nframes64_t frame, RegionPoint point, int32_t dir, Tra
 
                nframes64_t distance;
                boost::shared_ptr<Region> r;
-               
+
                track_speed = 1.0f;
                if ( (rtav = dynamic_cast<RouteTimeAxisView*>(*i)) != 0 ) {
-                       if (rtav->get_diskstream()!=0)
-                               track_speed = rtav->get_diskstream()->speed();
+                       if (rtav->track()!=0)
+                               track_speed = rtav->track()->speed();
                }
 
                track_frame = session_frame_to_track_frame(frame, track_speed);
@@ -737,7 +717,7 @@ Editor::find_next_region (nframes64_t frame, RegionPoint point, int32_t dir, Tra
                        break;
                }
 
-               // rpos is a "track frame", converting it to "session frame"
+               // rpos is a "track frame", converting it to "_session frame"
                rpos = track_frame_to_session_frame(rpos, track_speed);
 
                if (rpos > frame) {
@@ -785,7 +765,7 @@ Editor::find_next_region_boundary (nframes64_t pos, int32_t dir, const TrackView
                        distance = d;
                }
        }
-       
+
        return current_nearest;
 }
 
@@ -798,11 +778,11 @@ Editor::get_region_boundary (nframes64_t pos, int32_t dir, bool with_selection,
        if (with_selection && Config->get_region_boundaries_from_selected_tracks()) {
 
                if (!selection->tracks.empty()) {
-                       
+
                        target = find_next_region_boundary (pos, dir, selection->tracks);
-                       
+
                } else {
-                       
+
                        if (only_onscreen || Config->get_region_boundaries_from_onscreen_tracks()) {
                                get_onscreen_tracks (tvl);
                                target = find_next_region_boundary (pos, dir, tvl);
@@ -810,7 +790,7 @@ Editor::get_region_boundary (nframes64_t pos, int32_t dir, bool with_selection,
                                target = find_next_region_boundary (pos, dir, track_views);
                        }
                }
-               
+
        } else {
 
                if (only_onscreen || Config->get_region_boundaries_from_onscreen_tracks()) {
@@ -820,7 +800,7 @@ Editor::get_region_boundary (nframes64_t pos, int32_t dir, bool with_selection,
                        target = find_next_region_boundary (pos, dir, track_views);
                }
        }
-       
+
        return target;
 }
 
@@ -830,7 +810,7 @@ Editor::cursor_to_region_boundary (bool with_selection, int32_t dir)
        nframes64_t pos = playhead_cursor->current_frame;
        nframes64_t target;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -843,8 +823,7 @@ Editor::cursor_to_region_boundary (bool with_selection, int32_t dir)
                return;
        }
 
-
-       session->request_locate (target);
+       _session->request_locate (target);
 }
 
 void
@@ -865,7 +844,7 @@ Editor::cursor_to_region_point (EditorCursor* cursor, RegionPoint point, int32_t
        boost::shared_ptr<Region> r;
        nframes64_t pos = cursor->current_frame;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -876,25 +855,25 @@ Editor::cursor_to_region_point (EditorCursor* cursor, RegionPoint point, int32_t
                pos+=dir;
 
        if (!selection->tracks.empty()) {
-               
+
                r = find_next_region (pos, point, dir, selection->tracks, &ontrack);
-               
+
        } else if (clicked_axisview) {
-               
+
                TrackViewList t;
                t.push_back (clicked_axisview);
-               
+
                r = find_next_region (pos, point, dir, t, &ontrack);
-               
+
        } else {
-               
+
                r = find_next_region (pos, point, dir, track_views, &ontrack);
        }
 
        if (r == 0) {
                return;
        }
-       
+
        switch (point){
        case Start:
                pos = r->first_frame ();
@@ -907,22 +886,22 @@ Editor::cursor_to_region_point (EditorCursor* cursor, RegionPoint point, int32_t
        case SyncPoint:
                pos = r->sync_position ();
                // r->adjust_to_sync (r->first_frame());
-               break;  
+               break;
        }
-       
+
        float speed = 1.0f;
        RouteTimeAxisView *rtav;
 
        if ( ontrack != 0 && (rtav = dynamic_cast<RouteTimeAxisView*>(ontrack)) != 0 ) {
-               if (rtav->get_diskstream() != 0) {
-                       speed = rtav->get_diskstream()->speed();
+               if (rtav->track() != 0) {
+                       speed = rtav->track()->speed();
                }
        }
 
        pos = track_frame_to_session_frame(pos, speed);
-       
+
        if (cursor == playhead_cursor) {
-               session->request_locate (pos);
+               _session->request_locate (pos);
        } else {
                cursor->set_position (pos);
        }
@@ -944,7 +923,7 @@ void
 Editor::cursor_to_selection_start (EditorCursor *cursor)
 {
        nframes64_t pos = 0;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -966,7 +945,7 @@ Editor::cursor_to_selection_start (EditorCursor *cursor)
        }
 
        if (cursor == playhead_cursor) {
-               session->request_locate (pos);
+               _session->request_locate (pos);
        } else {
                cursor->set_position (pos);
        }
@@ -976,7 +955,7 @@ void
 Editor::cursor_to_selection_end (EditorCursor *cursor)
 {
        nframes64_t pos = 0;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -998,7 +977,7 @@ Editor::cursor_to_selection_end (EditorCursor *cursor)
        }
 
        if (cursor == playhead_cursor) {
-               session->request_locate (pos);
+               _session->request_locate (pos);
        } else {
                cursor->set_position (pos);
        }
@@ -1011,7 +990,7 @@ Editor::selected_marker_to_region_boundary (bool with_selection, int32_t dir)
        Location* loc;
        bool ignored;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -1022,7 +1001,7 @@ Editor::selected_marker_to_region_boundary (bool with_selection, int32_t dir)
                if (!mouse_frame (mouse, ignored)) {
                        return;
                }
-               
+
                add_location_mark (mouse);
        }
 
@@ -1064,7 +1043,7 @@ Editor::selected_marker_to_region_point (RegionPoint point, int32_t dir)
        Location* loc;
        bool ignored;
 
-       if (!session || selection->markers.empty()) {
+       if (!_session || selection->markers.empty()) {
                return;
        }
 
@@ -1081,18 +1060,18 @@ Editor::selected_marker_to_region_point (RegionPoint point, int32_t dir)
                pos+=dir;
 
        if (!selection->tracks.empty()) {
-               
+
                r = find_next_region (pos, point, dir, selection->tracks, &ontrack);
-               
+
        } else {
-               
+
                r = find_next_region (pos, point, dir, track_views, &ontrack);
        }
 
        if (r == 0) {
                return;
        }
-       
+
        switch (point){
        case Start:
                pos = r->first_frame ();
@@ -1104,15 +1083,15 @@ Editor::selected_marker_to_region_point (RegionPoint point, int32_t dir)
 
        case SyncPoint:
                pos = r->adjust_to_sync (r->first_frame());
-               break;  
+               break;
        }
-       
+
        float speed = 1.0f;
        RouteTimeAxisView *rtav;
 
        if (ontrack != 0 && (rtav = dynamic_cast<RouteTimeAxisView*>(ontrack)) != 0) {
-               if (rtav->get_diskstream() != 0) {
-                       speed = rtav->get_diskstream()->speed();
+               if (rtav->track() != 0) {
+                       speed = rtav->track()->speed();
                }
        }
 
@@ -1140,7 +1119,7 @@ Editor::selected_marker_to_selection_start ()
        Location* loc;
        bool ignored;
 
-       if (!session || selection->markers.empty()) {
+       if (!_session || selection->markers.empty()) {
                return;
        }
 
@@ -1148,7 +1127,7 @@ Editor::selected_marker_to_selection_start ()
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -1179,7 +1158,7 @@ Editor::selected_marker_to_selection_end ()
        Location* loc;
        bool ignored;
 
-       if (!session || selection->markers.empty()) {
+       if (!_session || selection->markers.empty()) {
                return;
        }
 
@@ -1187,7 +1166,7 @@ Editor::selected_marker_to_selection_end ()
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -1226,13 +1205,13 @@ Editor::scroll_playhead (bool forward)
                        pos += delta ;
                } else {
                        pos = max_frames;
-               } 
+               }
 
        } else {
 
                if (pos == 0) {
                        return;
-               } 
+               }
 
                if (pos > delta) {
                        pos -= delta;
@@ -1241,7 +1220,7 @@ Editor::scroll_playhead (bool forward)
                }
        }
 
-       session->request_locate (pos);
+       _session->request_locate (pos);
 }
 
 void
@@ -1256,7 +1235,7 @@ Editor::playhead_backward ()
                cnt = 1;
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate ());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate ());
                } else {
                        cnt = (nframes64_t) prefix;
                }
@@ -1269,13 +1248,13 @@ Editor::playhead_backward ()
        } else {
                pos -= cnt;
        }
-       
+
        /* XXX this is completely insane. with the current buffering
           design, we'll force a complete track buffer flush and
           reload, just to move 1 sample !!!
        */
 
-       session->request_locate (pos);
+       _session->request_locate (pos);
 }
 
 void
@@ -1290,26 +1269,26 @@ Editor::playhead_forward ()
                cnt = 1;
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate ());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate ());
                } else {
                        cnt = (nframes64_t) floor (prefix);
                }
        }
 
        pos = playhead_cursor->current_frame;
-       
+
        /* XXX this is completely insane. with the current buffering
           design, we'll force a complete track buffer flush and
           reload, just to move 1 sample !!!
        */
 
-       session->request_locate (pos+cnt);
+       _session->request_locate (pos+cnt);
 }
 
 void
 Editor::cursor_align (bool playhead_to_edit)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -1318,17 +1297,17 @@ Editor::cursor_align (bool playhead_to_edit)
                if (selection->markers.empty()) {
                        return;
                }
-               
-               session->request_locate (selection->markers.front()->position(), session->transport_rolling());
-       
+
+               _session->request_locate (selection->markers.front()->position(), _session->transport_rolling());
+
        } else {
                /* move selected markers to playhead */
-               
+
                for (MarkerSelection::iterator i = selection->markers.begin(); i != selection->markers.end(); ++i) {
                        bool ignored;
-                       
+
                        Location* loc = find_location_from_marker (*i, ignored);
-                       
+
                        if (loc->is_mark()) {
                                loc->set_start (playhead_cursor->current_frame);
                        } else {
@@ -1351,7 +1330,7 @@ Editor::edit_cursor_backward ()
                cnt = 1;
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate ());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate ());
                } else {
                        cnt = (nframes64_t) prefix;
                }
@@ -1366,7 +1345,7 @@ Editor::edit_cursor_backward ()
        } else {
                pos -= cnt;
        }
-       
+
        // EDIT CURSOR edit_cursor->set_position (pos);
 }
 
@@ -1382,7 +1361,7 @@ Editor::edit_cursor_forward ()
                cnt = 1;
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate ());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate ());
                } else {
                        cnt = (nframes64_t) floor (prefix);
                }
@@ -1404,28 +1383,28 @@ Editor::goto_frame ()
        }
 
        if (was_floating) {
-               frame = (nframes64_t) floor (prefix * session->frame_rate());
+               frame = (nframes64_t) floor (prefix * _session->frame_rate());
        } else {
                frame = (nframes64_t) floor (prefix);
        }
 
-       session->request_locate (frame);
+       _session->request_locate (frame);
 }
 
 void
 Editor::scroll_backward (float pages)
 {
        nframes64_t frame;
-       nframes64_t one_page = (nframes64_t) rint (canvas_width * frames_per_unit);
+       nframes64_t one_page = (nframes64_t) rint (_canvas_width * frames_per_unit);
        bool was_floating;
        float prefix;
        nframes64_t cnt;
-       
+
        if (get_prefix (prefix, was_floating)) {
                cnt = (nframes64_t) floor (pages * one_page);
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate());
                } else {
                        cnt = (nframes64_t) floor (prefix * one_page);
                }
@@ -1444,16 +1423,16 @@ void
 Editor::scroll_forward (float pages)
 {
        nframes64_t frame;
-       nframes64_t one_page = (nframes64_t) rint (canvas_width * frames_per_unit);
+       nframes64_t one_page = (nframes64_t) rint (_canvas_width * frames_per_unit);
        bool was_floating;
        float prefix;
        nframes64_t cnt;
-       
+
        if (get_prefix (prefix, was_floating)) {
                cnt = (nframes64_t) floor (pages * one_page);
        } else {
                if (was_floating) {
-                       cnt = (nframes64_t) floor (prefix * session->frame_rate());
+                       cnt = (nframes64_t) floor (prefix * _session->frame_rate());
                } else {
                        cnt = (nframes64_t) floor (prefix * one_page);
                }
@@ -1483,8 +1462,8 @@ Editor::scroll_tracks_down ()
 
        double vert_value = vertical_adjustment.get_value() + (cnt *
                vertical_adjustment.get_page_size());
-       if (vert_value > vertical_adjustment.get_upper() - canvas_height) {
-               vert_value = vertical_adjustment.get_upper() - canvas_height;
+       if (vert_value > vertical_adjustment.get_upper() - _canvas_height) {
+               vert_value = vertical_adjustment.get_upper() - _canvas_height;
        }
        vertical_adjustment.set_value (vert_value);
 }
@@ -1508,48 +1487,61 @@ Editor::scroll_tracks_up ()
 void
 Editor::scroll_tracks_down_line ()
 {
+       double vert_value = vertical_adjustment.get_value() + 60;
 
-        Gtk::Adjustment* adj = edit_vscrollbar.get_adjustment();
-       double vert_value = adj->get_value() + 60;
-
-       if (vert_value>adj->get_upper() - canvas_height) {
-               vert_value = adj->get_upper() - canvas_height;
+       if (vert_value > vertical_adjustment.get_upper() - _canvas_height) {
+               vert_value = vertical_adjustment.get_upper() - _canvas_height;
        }
-       adj->set_value (vert_value);
+       
+       vertical_adjustment.set_value (vert_value);
 }
 
 void
 Editor::scroll_tracks_up_line ()
 {
-        Gtk::Adjustment* adj = edit_vscrollbar.get_adjustment();
-       adj->set_value (adj->get_value() - 60);
+       reset_y_origin (vertical_adjustment.get_value() - 60);
 }
 
 /* ZOOM */
 
+void
+Editor::tav_zoom_step (bool coarser)
+{
+       ENSURE_GUI_THREAD (*this, &Editor::temporal_zoom_step, coarser)
+
+       _routes->suspend_redisplay ();
+
+       for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
+               TimeAxisView *tv = (static_cast<TimeAxisView*>(*i));
+                       tv->step_height (coarser);
+       }
+
+       _routes->resume_redisplay ();
+}
+
 void
 Editor::temporal_zoom_step (bool coarser)
 {
-       ENSURE_GUI_THREAD (bind (mem_fun (*this, &Editor::temporal_zoom_step), coarser));
+       ENSURE_GUI_THREAD (*this, &Editor::temporal_zoom_step, coarser)
 
        double nfpu;
 
        nfpu = frames_per_unit;
-       
-       if (coarser) { 
+
+       if (coarser) {
                nfpu *= 1.61803399;
-       } else { 
+       } else {
                nfpu = max(1.0,(nfpu/1.61803399));
        }
 
        temporal_zoom (nfpu);
-}      
+}
 
 void
 Editor::temporal_zoom (gdouble fpu)
 {
-       if (!session) return;
-       
+       if (!_session) return;
+
        nframes64_t current_page = current_page_frames();
        nframes64_t current_leftmost = leftmost_frame;
        nframes64_t current_rightmost;
@@ -1564,20 +1556,20 @@ Editor::temporal_zoom (gdouble fpu)
 
        /* XXX this limit is also in ::set_frames_per_unit() */
 
-       if (frames_per_unit <= 2.0 && fpu <= frames_per_unit) {
+       if (frames_per_unit <= 1.0 && fpu <= frames_per_unit) {
                return;
        }
 
        nfpu = fpu;
-       
-       new_page_size = (nframes64_t) floor (canvas_width * nfpu);
+
+       new_page_size = (nframes64_t) floor (_canvas_width * nfpu);
        half_page_size = new_page_size / 2;
 
        switch (zoom_focus) {
        case ZoomFocusLeft:
                leftmost_after_zoom = current_leftmost;
                break;
-               
+
        case ZoomFocusRight:
                current_rightmost = leftmost_frame + current_page;
                if (current_rightmost < new_page_size) {
@@ -1586,26 +1578,23 @@ Editor::temporal_zoom (gdouble fpu)
                        leftmost_after_zoom = current_rightmost - new_page_size;
                }
                break;
-               
+
        case ZoomFocusCenter:
-               current_center = current_leftmost + (current_page/2); 
+               current_center = current_leftmost + (current_page/2);
                if (current_center < half_page_size) {
                        leftmost_after_zoom = 0;
                } else {
                        leftmost_after_zoom = current_center - half_page_size;
                }
                break;
-               
-       case ZoomFocusPlayhead:
-               /* try to keep the playhead in the same place */
 
-               where = playhead_cursor->current_frame;
-               
-               l = - ((new_page_size * ((where - current_leftmost)/(double)current_page)) - where);
+       case ZoomFocusPlayhead:
+               /* centre playhead */
+               l = playhead_cursor->current_frame - (new_page_size * 0.5);
 
                if (l < 0) {
                        leftmost_after_zoom = 0;
-               } else if (l > max_frames) { 
+               } else if (l > max_frames) {
                        leftmost_after_zoom = max_frames - new_page_size;
                } else {
                        leftmost_after_zoom = (nframes64_t) l;
@@ -1631,7 +1620,7 @@ Editor::temporal_zoom (gdouble fpu)
 
                        if (l < 0) {
                                leftmost_after_zoom = 0;
-                       } else if (l > max_frames) { 
+                       } else if (l > max_frames) {
                                leftmost_after_zoom = max_frames - new_page_size;
                        } else {
                                leftmost_after_zoom = (nframes64_t) l;
@@ -1650,7 +1639,7 @@ Editor::temporal_zoom (gdouble fpu)
 
                        if (l < 0) {
                                leftmost_after_zoom = 0;
-                       } else if (l > max_frames) { 
+                       } else if (l > max_frames) {
                                leftmost_after_zoom = max_frames - new_page_size;
                        } else {
                                leftmost_after_zoom = (nframes64_t) l;
@@ -1661,13 +1650,13 @@ Editor::temporal_zoom (gdouble fpu)
                        return;
                }
                break;
-               
+
        }
-       // leftmost_after_zoom = min (leftmost_after_zoom, session->current_end_frame());
+
+       // leftmost_after_zoom = min (leftmost_after_zoom, _session->current_end_frame());
 
        reposition_and_zoom (leftmost_after_zoom, nfpu);
-}      
+}
 
 void
 Editor::temporal_zoom_region (bool both_axes)
@@ -1675,7 +1664,7 @@ Editor::temporal_zoom_region (bool both_axes)
 
        nframes64_t start = max_frames;
        nframes64_t end = 0;
-       RegionSelection rs; 
+       RegionSelection rs;
        set<TimeAxisView*> tracks;
 
        get_regions_for_action (rs);
@@ -1713,14 +1702,14 @@ Editor::temporal_zoom_region (bool both_axes)
        }
 
        nframes64_t range = end - start;
-       double new_fpu = (double)range / (double)canvas_width;
+       double new_fpu = (double)range / (double)_canvas_width;
        nframes64_t extra_samples = (nframes64_t) floor (one_centimeter_in_pixels * new_fpu);
 
        if (start > extra_samples) {
                start -= extra_samples;
        } else {
                start = 0;
-       } 
+       }
 
        if (max_frames - extra_samples > end) {
                end += extra_samples;
@@ -1739,17 +1728,17 @@ Editor::temporal_zoom_region (bool both_axes)
        temporal_zoom_by_frame (start, end, "zoom to region");
 
        if (both_axes) {
-               uint32_t per_track_height = (uint32_t) floor ((canvas_height - canvas_timebars_vsize - 10.0) / tracks.size());
-               
+               uint32_t per_track_height = (uint32_t) floor ((_canvas_height - canvas_timebars_vsize - 10.0) / tracks.size());
+
                /* set visible track heights appropriately */
-               
+
                for (set<TimeAxisView*>::iterator t = tracks.begin(); t != tracks.end(); ++t) {
                        (*t)->set_height (per_track_height);
                }
-               
+
                /* hide irrelevant tracks */
-               
-               no_route_list_redisplay = true;
+
+               _routes->suspend_redisplay ();
 
                for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
                        if (find (tracks.begin(), tracks.end(), (*i)) == tracks.end()) {
@@ -1757,32 +1746,26 @@ Editor::temporal_zoom_region (bool both_axes)
                        }
                }
 
-               no_route_list_redisplay = false;
-               redisplay_route_list ();
+               _routes->resume_redisplay ();
 
                vertical_adjustment.set_value (0.0);
                no_save_visual = false;
        }
 
-       zoomed_to_region = true;
        redo_visual_stack.push_back (current_visual_state());
 }
 
 void
-Editor::toggle_zoom_region (bool both_axes)
+Editor::zoom_to_region (bool both_axes)
 {
-       if (zoomed_to_region) {
-               swap_visual_state ();
-       } else {
-               temporal_zoom_region (both_axes);
-       }
+       temporal_zoom_region (both_axes);
 }
 
 void
 Editor::temporal_zoom_selection ()
 {
        if (!selection) return;
-       
+
        if (selection->time.empty()) {
                return;
        }
@@ -1796,17 +1779,17 @@ Editor::temporal_zoom_selection ()
 void
 Editor::temporal_zoom_session ()
 {
-       ENSURE_GUI_THREAD (mem_fun (*this, &Editor::temporal_zoom_session));
+       ENSURE_GUI_THREAD (*this, &Editor::temporal_zoom_session)
 
-       if (session) {
-               temporal_zoom_by_frame (session->current_start_frame(), session->current_end_frame(), "zoom to session");
+       if (_session) {
+               temporal_zoom_by_frame (_session->current_start_frame(), _session->current_end_frame(), "zoom to _session");
        }
 }
 
 void
-Editor::temporal_zoom_by_frame (nframes64_t start, nframes64_t end, const string & op)
+Editor::temporal_zoom_by_frame (nframes64_t start, nframes64_t end, const string & /*op*/)
 {
-       if (!session) return;
+       if (!_session) return;
 
        if ((start == 0 && end == 0) || end < start) {
                return;
@@ -1814,9 +1797,9 @@ Editor::temporal_zoom_by_frame (nframes64_t start, nframes64_t end, const string
 
        nframes64_t range = end - start;
 
-       double new_fpu = (double)range / (double)canvas_width;
-       
-       nframes64_t new_page = (nframes64_t) floor (canvas_width * new_fpu);
+       double new_fpu = (double)range / (double)_canvas_width;
+
+       nframes64_t new_page = (nframes64_t) floor (_canvas_width * new_fpu);
        nframes64_t middle = (nframes64_t) floor( (double)start + ((double)range / 2.0f ));
        nframes64_t new_leftmost = (nframes64_t) floor( (double)middle - ((double)new_page/2.0f));
 
@@ -1827,21 +1810,21 @@ Editor::temporal_zoom_by_frame (nframes64_t start, nframes64_t end, const string
        reposition_and_zoom (new_leftmost, new_fpu);
 }
 
-void 
+void
 Editor::temporal_zoom_to_frame (bool coarser, nframes64_t frame)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
        double range_before = frame - leftmost_frame;
        double new_fpu;
-       
+
        new_fpu = frames_per_unit;
-       
-       if (coarser) { 
+
+       if (coarser) {
                new_fpu *= 1.61803399;
                range_before *= 1.61803399;
-       } else { 
+       } else {
                new_fpu = max(1.0,(new_fpu/1.61803399));
                range_before /= 1.61803399;
        }
@@ -1856,8 +1839,8 @@ Editor::temporal_zoom_to_frame (bool coarser, nframes64_t frame)
                new_leftmost = 0;
        }
 //     begin_reversible_command (_("zoom to frame"));
-//     session->add_undo (bind (mem_fun(*this, &Editor::reposition_and_zoom), leftmost_frame, frames_per_unit));
-//     session->add_redo (bind (mem_fun(*this, &Editor::reposition_and_zoom), new_leftmost, new_fpu));
+//     _session->add_undo (sigc::bind (sigc::mem_fun(*this, &Editor::reposition_and_zoom), leftmost_frame, frames_per_unit));
+//     _session->add_redo (sigc::bind (sigc::mem_fun(*this, &Editor::reposition_and_zoom), new_leftmost, new_fpu));
 //     commit_reversible_command ();
 
        reposition_and_zoom (new_leftmost, new_fpu);
@@ -1876,10 +1859,7 @@ Editor::choose_new_marker_name(string &name) {
 
        dialog.set_prompt (_("New Name:"));
 
-       WindowTitle title(Glib::get_application_name());
-       title += _("Name New Location Marker");
-
-       dialog.set_title(title.get_string());
+       dialog.set_title (_("New Location Marker"));
 
        dialog.set_name ("MarkNameWindow");
        dialog.set_size_request (250, -1);
@@ -1896,7 +1876,7 @@ Editor::choose_new_marker_name(string &name) {
        default:
                return false;
        }
-       
+
        dialog.get_result(name);
        return true;
 
@@ -1912,22 +1892,22 @@ Editor::add_location_from_selection ()
                return;
        }
 
-       if (session == 0 || clicked_axisview == 0) {
+       if (_session == 0 || clicked_axisview == 0) {
                return;
        }
 
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
 
-       session->locations()->next_available_name(rangename,"selection");
+       _session->locations()->next_available_name(rangename,"selection");
        Location *location = new Location (start, end, rangename, Location::IsRangeMarker);
 
-       session->begin_reversible_command (_("add marker"));
-        XMLNode &before = session->locations()->get_state();
-       session->locations()->add (location, true);
-        XMLNode &after = session->locations()->get_state();
-       session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
-       session->commit_reversible_command ();
+       _session->begin_reversible_command (_("add marker"));
+        XMLNode &before = _session->locations()->get_state();
+       _session->locations()->add (location, true);
+        XMLNode &after = _session->locations()->get_state();
+       _session->add_command(new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+       _session->commit_reversible_command ();
 }
 
 void
@@ -1937,29 +1917,29 @@ Editor::add_location_mark (nframes64_t where)
 
        select_new_marker = true;
 
-       session->locations()->next_available_name(markername,"mark");
+       _session->locations()->next_available_name(markername,"mark");
        if (!choose_new_marker_name(markername)) {
                return;
        }
        Location *location = new Location (where, where, markername, Location::IsMark);
-       session->begin_reversible_command (_("add marker"));
-        XMLNode &before = session->locations()->get_state();
-       session->locations()->add (location, true);
-        XMLNode &after = session->locations()->get_state();
-       session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
-       session->commit_reversible_command ();
+       _session->begin_reversible_command (_("add marker"));
+        XMLNode &before = _session->locations()->get_state();
+       _session->locations()->add (location, true);
+        XMLNode &after = _session->locations()->get_state();
+       _session->add_command(new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::add_location_from_playhead_cursor ()
 {
-       add_location_mark (session->audible_frame());
+       add_location_mark (_session->audible_frame());
 }
 
 void
 Editor::add_locations_from_audio_region ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -1967,29 +1947,29 @@ Editor::add_locations_from_audio_region ()
                return;
        }
 
-       session->begin_reversible_command (rs.size () > 1 ? _("add markers") : _("add marker"));
-       XMLNode &before = session->locations()->get_state();
-       
+       _session->begin_reversible_command (rs.size () > 1 ? _("add markers") : _("add marker"));
+       XMLNode &before = _session->locations()->get_state();
+
        cerr << "Add locations\n";
 
        for (RegionSelection::iterator i = rs.begin (); i != rs.end (); ++i) {
-               
+
                boost::shared_ptr<Region> region = (*i)->region ();
-       
+
                Location *location = new Location (region->position(), region->last_frame(), region->name(), Location::IsRangeMarker);
-               
-               session->locations()->add (location, true);
+
+               _session->locations()->add (location, true);
        }
 
-       XMLNode &after = session->locations()->get_state();
-       session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
-       session->commit_reversible_command ();
+       XMLNode &after = _session->locations()->get_state();
+       _session->add_command (new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::add_location_from_audio_region ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -1997,32 +1977,32 @@ Editor::add_location_from_audio_region ()
                return;
        }
 
-       session->begin_reversible_command (_("add marker"));
-       XMLNode &before = session->locations()->get_state();
+       _session->begin_reversible_command (_("add marker"));
+       XMLNode &before = _session->locations()->get_state();
 
        string markername;
 
        if (rs.size() > 1) {            // more than one region selected
-               session->locations()->next_available_name(markername, "regions");
+               _session->locations()->next_available_name(markername, "regions");
        } else {
                RegionView* rv = *(rs.begin());
                boost::shared_ptr<Region> region = rv->region();
                markername = region->name();
        }
-               
+
        if (!choose_new_marker_name(markername)) {
                return;
        }
 
        cerr << "Add location\n";
 
-       // single range spanning all selected 
+       // single range spanning all selected
        Location *location = new Location (rs.start(), rs.end_frame(), markername, Location::IsRangeMarker);
-       session->locations()->add (location, true);
+       _session->locations()->add (location, true);
 
-       XMLNode &after = session->locations()->get_state();
-       session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
-       session->commit_reversible_command ();
+       XMLNode &after = _session->locations()->get_state();
+       _session->add_command (new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+       _session->commit_reversible_command ();
 }
 
 void
@@ -2043,7 +2023,7 @@ Editor::amplitude_zoom_step (bool in)
 #ifdef FIX_FOR_CANVAS
        /* XXX DO SOMETHING */
 #endif
-}      
+}
 
 
 /* DELETION */
@@ -2083,32 +2063,32 @@ Editor::search_forwards ()
 void
 Editor::jump_forward_to_mark ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
-       
-       Location *location = session->locations()->first_location_after (playhead_cursor->current_frame);
+
+       Location *location = _session->locations()->first_location_after (playhead_cursor->current_frame);
 
        if (location) {
-               session->request_locate (location->start(), session->transport_rolling());
+               _session->request_locate (location->start(), _session->transport_rolling());
        } else {
-               session->request_locate (session->current_end_frame());
+               _session->request_locate (_session->current_end_frame());
        }
 }
 
 void
 Editor::jump_backward_to_mark ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       Location *location = session->locations()->first_location_before (playhead_cursor->current_frame);
-       
+       Location *location = _session->locations()->first_location_before (playhead_cursor->current_frame);
+
        if (location) {
-               session->request_locate (location->start(), session->transport_rolling());
+               _session->request_locate (location->start(), _session->transport_rolling());
        } else {
-               session->goto_start ();
+               _session->goto_start ();
        }
 }
 
@@ -2121,66 +2101,66 @@ Editor::set_mark ()
        string markername;
 
        if (get_prefix (prefix, was_floating)) {
-               pos = session->audible_frame ();
+               pos = _session->audible_frame ();
        } else {
                if (was_floating) {
-                       pos = (nframes64_t) floor (prefix * session->frame_rate ());
+                       pos = (nframes64_t) floor (prefix * _session->frame_rate ());
                } else {
                        pos = (nframes64_t) floor (prefix);
                }
        }
 
-       session->locations()->next_available_name(markername,"mark");
+       _session->locations()->next_available_name(markername,"mark");
        if (!choose_new_marker_name(markername)) {
                return;
        }
-       session->locations()->add (new Location (pos, 0, markername, Location::IsMark), true);
+       _session->locations()->add (new Location (pos, 0, markername, Location::IsMark), true);
 }
 
 void
 Editor::clear_markers ()
 {
-       if (session) {
-               session->begin_reversible_command (_("clear markers"));
-                XMLNode &before = session->locations()->get_state();
-               session->locations()->clear_markers ();
-                XMLNode &after = session->locations()->get_state();
-               session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
-               session->commit_reversible_command ();
+       if (_session) {
+               _session->begin_reversible_command (_("clear markers"));
+                XMLNode &before = _session->locations()->get_state();
+               _session->locations()->clear_markers ();
+                XMLNode &after = _session->locations()->get_state();
+               _session->add_command(new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+               _session->commit_reversible_command ();
        }
 }
 
 void
 Editor::clear_ranges ()
 {
-       if (session) {
-               session->begin_reversible_command (_("clear ranges"));
-                XMLNode &before = session->locations()->get_state();
-               
-               Location * looploc = session->locations()->auto_loop_location();
-               Location * punchloc = session->locations()->auto_punch_location();
-               
-               session->locations()->clear_ranges ();
+       if (_session) {
+               _session->begin_reversible_command (_("clear ranges"));
+                XMLNode &before = _session->locations()->get_state();
+
+               Location * looploc = _session->locations()->auto_loop_location();
+               Location * punchloc = _session->locations()->auto_punch_location();
+
+               _session->locations()->clear_ranges ();
                // re-add these
-               if (looploc) session->locations()->add (looploc);
-               if (punchloc) session->locations()->add (punchloc);
-               
-                XMLNode &after = session->locations()->get_state();
-               session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
-               session->commit_reversible_command ();
+               if (looploc) _session->locations()->add (looploc);
+               if (punchloc) _session->locations()->add (punchloc);
+
+                XMLNode &after = _session->locations()->get_state();
+               _session->add_command(new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+               _session->commit_reversible_command ();
        }
 }
 
 void
 Editor::clear_locations ()
 {
-       session->begin_reversible_command (_("clear locations"));
-        XMLNode &before = session->locations()->get_state();
-       session->locations()->clear ();
-        XMLNode &after = session->locations()->get_state();
-       session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
-       session->commit_reversible_command ();
-       session->locations()->clear ();
+       _session->begin_reversible_command (_("clear locations"));
+        XMLNode &before = _session->locations()->get_state();
+       _session->locations()->clear ();
+        XMLNode &after = _session->locations()->get_state();
+       _session->add_command(new MementoCommand<Locations>(*(_session->locations()), &before, &after));
+       _session->commit_reversible_command ();
+       _session->locations()->clear ();
 }
 
 void
@@ -2199,7 +2179,7 @@ Editor::unhide_ranges ()
 {
        for (LocationMarkerMap::iterator i = location_markers.begin(); i != location_markers.end(); ++i) {
                Location *l = (*i).first;
-               if (l->is_hidden() && l->is_range_marker()) { 
+               if (l->is_hidden() && l->is_range_marker()) {
                        l->set_hidden(false, this);
                }
        }
@@ -2215,7 +2195,7 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        nframes64_t where;
        RouteTimeAxisView *rtv = 0;
        boost::shared_ptr<Playlist> playlist;
-       
+
        track_canvas->window_to_world (x, y, wx, wy);
        //wx += horizontal_adjustment.get_value();
        //wy += vertical_adjustment.get_value();
@@ -2224,7 +2204,7 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        event.type = GDK_BUTTON_RELEASE;
        event.button.x = wx;
        event.button.y = wy;
-       
+
        where = event_frame (&event, &cx, &cy);
 
        if (where < leftmost_frame || where > leftmost_frame + current_page_frames()) {
@@ -2236,7 +2216,7 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        if (tv.first == 0) {
                return;
        }
-       
+
        if ((rtv = dynamic_cast<RouteTimeAxisView*> (tv.first)) == 0) {
                return;
        }
@@ -2244,13 +2224,13 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        if ((playlist = rtv->playlist()) == 0) {
                return;
        }
-       
+
        snap_to (where);
-       
+
        begin_reversible_command (_("insert dragged region"));
-        XMLNode &before = playlist->get_state();
+        playlist->clear_history ();
        playlist->add_region (RegionFactory::create (region), where, 1.0);
-       session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
+       _session->add_command(new StatefulDiffCommand (playlist));
        commit_reversible_command ();
 }
 
@@ -2282,13 +2262,13 @@ Editor::insert_route_list_drag (boost::shared_ptr<Route> route, int x, int y) {
                return;
        }
 
-       /* use this drag source to add underlay to a track. But we really don't care 
+       /* use this drag source to add underlay to a track. But we really don't care
           about the Route, only the view of the route, so find it first */
        for(TrackViewList::iterator it = track_views.begin(); it != track_views.end(); ++it) {
                if((source_rtv = dynamic_cast<RouteTimeAxisView*>(*it)) == 0) {
                        continue;
                }
-               
+
                if(source_rtv->route() == route && source_rtv != dest_rtv) {
                        dest_rtv->add_underlay(source_rtv->view());
                        break;
@@ -2319,29 +2299,17 @@ Editor::insert_region_list_selection (float times)
        if ((playlist = tv->playlist()) == 0) {
                return;
        }
-       
-       Glib::RefPtr<TreeSelection> selected = region_list_display.get_selection();
-       
-       if (selected->count_selected_rows() != 1) {
+
+       boost::shared_ptr<Region> region = _regions->get_single_selection ();
+       if (region == 0) {
                return;
        }
-       
-       TreeView::Selection::ListHandle_Path rows = selected->get_selected_rows ();
-
-       /* only one row selected, so rows.begin() is it */
-
-       TreeIter iter;
 
-       if ((iter = region_list_model->get_iter (*rows.begin()))) {
-
-               boost::shared_ptr<Region> region = (*iter)[region_list_columns.region];
-               
-               begin_reversible_command (_("insert region"));
-               XMLNode &before = playlist->get_state();
-               playlist->add_region ((RegionFactory::create (region)), get_preferred_edit_position(), times);
-               session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
-               commit_reversible_command ();
-       } 
+       begin_reversible_command (_("insert region"));
+        playlist->clear_history ();
+       playlist->add_region ((RegionFactory::create (region)), get_preferred_edit_position(), times);
+       _session->add_command(new StatefulDiffCommand (playlist));
+       commit_reversible_command ();
 }
 
 /* BUILT-IN EFFECTS */
@@ -2364,68 +2332,38 @@ Editor::edit_envelope ()
 void
 Editor::transition_to_rolling (bool fwd)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       switch (Config->get_slave_source()) {
-       case None:
-       case JACK:
-               break;
-       default:
-               /* transport controlled by the master */
-               return;
-       }
-
-       if (session->is_auditioning()) {
-               session->cancel_audition ();
-               return;
-       }
-       
-       session->request_transport_speed (fwd ? 1.0f : -1.0f);
-}
-
-void
-Editor::toggle_playback (bool with_abort)
-{
-       if (!session) {
-               return;
+       if (_session->config.get_external_sync()) {
+               switch (_session->config.get_sync_source()) {
+               case JACK:
+                       break;
+               default:
+                       /* transport controlled by the master */
+                       return;
+               }
        }
 
-       switch (Config->get_slave_source()) {
-       case None:
-       case JACK:
-               break;
-       default:
-               /* transport controlled by the master */
+       if (_session->is_auditioning()) {
+               _session->cancel_audition ();
                return;
        }
 
-       if (session->is_auditioning()) {
-               session->cancel_audition ();
-               return;
-       }
-       
-       if (session->transport_rolling()) {
-               session->request_stop (with_abort);
-               if (session->get_play_loop()) {
-                       session->request_play_loop (false);
-               }
-       } else {
-               session->request_transport_speed (1.0f);
-       }
+       _session->request_transport_speed (fwd ? 1.0f : -1.0f);
 }
 
 void
 Editor::play_from_start ()
 {
-       session->request_locate (session->current_start_frame(), true);
+       _session->request_locate (_session->current_start_frame(), true);
 }
 
 void
 Editor::play_from_edit_point ()
 {
-       session->request_locate (get_preferred_edit_position(), true);
+       _session->request_locate (get_preferred_edit_position(), true);
 }
 
 void
@@ -2436,19 +2374,19 @@ Editor::play_from_edit_point_and_return ()
 
        start_frame = get_preferred_edit_position (true);
 
-       if (session->transport_rolling()) {
-               session->request_locate (start_frame, false);
+       if (_session->transport_rolling()) {
+               _session->request_locate (start_frame, false);
                return;
        }
 
        /* don't reset the return frame if its already set */
 
-       if ((return_frame = session->requested_return_frame()) < 0) {
-               return_frame = session->audible_frame();
+       if ((return_frame = _session->requested_return_frame()) < 0) {
+               return_frame = _session->audible_frame();
        }
 
        if (start_frame >= 0) {
-               session->request_roll_at_and_return (start_frame, return_frame);
+               _session->request_roll_at_and_return (start_frame, return_frame);
        }
 }
 
@@ -2459,13 +2397,13 @@ Editor::play_selection ()
                return;
        }
 
-       session->request_play_range (true);
+       _session->request_play_range (&selection->time, true);
 }
 
 void
 Editor::loop_selected_region ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -2476,12 +2414,12 @@ Editor::loop_selected_region ()
                if ((tll = transport_loop_location()) != 0)  {
 
                        tll->set (rv->region()->position(), rv->region()->last_frame());
-                       
+
                        // enable looping, reposition and start rolling
 
-                       session->request_play_loop (true);
-                       session->request_locate (tll->start(), false);
-                       session->request_transport_speed (1.0f);
+                       _session->request_play_loop (true);
+                       _session->request_locate (tll->start(), false);
+                       _session->request_transport_speed (1.0f);
                }
        }
 }
@@ -2493,7 +2431,7 @@ Editor::play_location (Location& location)
                return;
        }
 
-       session->request_bounded_roll (location.start(), location.end());
+       _session->request_bounded_roll (location.start(), location.end());
 }
 
 void
@@ -2509,8 +2447,8 @@ Editor::loop_location (Location& location)
                tll->set (location.start(), location.end());
 
                // enable looping, reposition and start rolling
-               session->request_play_loop (true);
-               session->request_locate (tll->start(), true);
+               _session->request_play_loop (true);
+               _session->request_locate (tll->start(), true);
        }
 }
 
@@ -2545,10 +2483,17 @@ Editor::edit_region ()
        selection->foreach_regionview (&RegionView::show_region_editor);
 }
 
+/** Show the midi list editor for the selected MIDI regions */
+void
+Editor::show_midi_list_editor ()
+{
+       selection->foreach_midi_regionview (&MidiRegionView::show_list_editor);
+}
+
 void
 Editor::rename_region()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -2556,10 +2501,7 @@ Editor::rename_region()
                return;
        }
 
-       WindowTitle title (Glib::get_application_name());
-       title += _("Rename Region");
-
-       ArdourDialog d (*this, title.get_string(), true, false);
+       ArdourDialog d (*this, _("Rename Region"), true, false);
        Entry entry;
        Label label (_("New name:"));
        HBox hbox;
@@ -2571,8 +2513,8 @@ Editor::rename_region()
        d.get_vbox()->set_border_width (12);
        d.get_vbox()->pack_start (hbox, false, false);
 
-       d.add_button(Gtk::Stock::OK, Gtk::RESPONSE_OK);
        d.add_button(Gtk::Stock::CANCEL, Gtk::RESPONSE_CANCEL);
+       d.add_button(Gtk::Stock::OK, Gtk::RESPONSE_OK);
 
        d.set_size_request (300, -1);
        d.set_position (Gtk::WIN_POS_MOUSE);
@@ -2580,10 +2522,10 @@ Editor::rename_region()
        entry.set_text (rs.front()->region()->name());
        entry.select_region (0, -1);
 
-       entry.signal_activate().connect (bind (mem_fun (d, &Dialog::response), RESPONSE_OK));
-       
+       entry.signal_activate().connect (sigc::bind (sigc::mem_fun (d, &Dialog::response), RESPONSE_OK));
+
        d.show_all ();
-       
+
        entry.grab_focus();
 
        int ret = d.run();
@@ -2595,7 +2537,7 @@ Editor::rename_region()
                strip_whitespace_edges (str);
                if (!str.empty()) {
                        rs.front()->region()->set_name (str);
-                       redisplay_regions ();
+                       _regions->redisplay ();
                }
        }
 }
@@ -2603,9 +2545,9 @@ Editor::rename_region()
 void
 Editor::audition_playlist_region_via_route (boost::shared_ptr<Region> region, Route& route)
 {
-       if (session->is_auditioning()) {
-               session->cancel_audition ();
-       } 
+       if (_session->is_auditioning()) {
+               _session->cancel_audition ();
+       }
 
        // note: some potential for creativity here, because region doesn't
        // have to belong to the playlist that Route is handling
@@ -2613,9 +2555,9 @@ Editor::audition_playlist_region_via_route (boost::shared_ptr<Region> region, Ro
        // bool was_soloed = route.soloed();
 
        route.set_solo (true, this);
-       
-       session->request_bounded_roll (region->position(), region->position() + region->length());
-       
+
+       _session->request_bounded_roll (region->position(), region->position() + region->length());
+
        /* XXX how to unset the solo state ? */
 }
 
@@ -2626,7 +2568,7 @@ Editor::play_edit_range ()
        nframes64_t start, end;
 
        if (get_edit_op_range (start, end)) {
-               session->request_bounded_roll (start, end);
+               _session->request_bounded_roll (start, end);
        }
 }
 
@@ -2635,10 +2577,10 @@ Editor::play_selected_region ()
 {
        nframes64_t start = max_frames;
        nframes64_t end = 0;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
-        
+
        if (rs.empty()) {
                return;
        }
@@ -2652,47 +2594,13 @@ Editor::play_selected_region ()
                }
        }
 
-       session->request_stop ();
-       session->request_bounded_roll (start, end);
+       _session->request_bounded_roll (start, end);
 }
 
 void
 Editor::audition_playlist_region_standalone (boost::shared_ptr<Region> region)
 {
-       session->audition_region (region);
-}
-
-void
-Editor::build_interthread_progress_window ()
-{
-       interthread_progress_window = new ArdourDialog (X_("interthread progress"), true);
-
-       interthread_progress_bar.set_orientation (Gtk::PROGRESS_LEFT_TO_RIGHT);
-       
-       interthread_progress_window->set_border_width (12);
-       interthread_progress_window->get_vbox()->set_spacing (6);
-
-       interthread_progress_label.set_alignment (0.5, 0.5);
-
-       interthread_progress_window->get_vbox()->pack_start (interthread_progress_label, false, false);
-       interthread_progress_window->get_vbox()->pack_start (interthread_progress_bar,false, false);
-
-       // GTK2FIX: this button needs a modifiable label
-
-       Button* b = interthread_progress_window->add_button (Stock::CANCEL, RESPONSE_CANCEL);
-       b->signal_clicked().connect (mem_fun(*this, &Editor::interthread_cancel_clicked));
-
-       interthread_cancel_button.add (interthread_cancel_label);
-
-       interthread_progress_window->set_default_size (200, 100);
-}
-
-void
-Editor::interthread_cancel_clicked ()
-{
-       if (current_interthread_info) {
-               current_interthread_info->cancel = true;
-       }
+       _session->audition_region (region);
 }
 
 void
@@ -2709,9 +2617,11 @@ Editor::region_from_selection ()
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
 
+       TrackViewList tracks = get_tracks_for_range_action ();
+
        nframes64_t selection_cnt = end - start + 1;
-       
-       for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
+
+       for (TrackSelection::iterator i = tracks.begin(); i != tracks.end(); ++i) {
                boost::shared_ptr<Region> current;
                boost::shared_ptr<Playlist> pl;
                nframes64_t internal_start;
@@ -2726,11 +2636,18 @@ Editor::region_from_selection ()
                }
 
                internal_start = start - current->position();
-               session->region_name (new_name, current->name(), true);
-               boost::shared_ptr<Region> region (RegionFactory::create (current,
-                               internal_start, selection_cnt, new_name));
+               RegionFactory::region_name (new_name, current->name(), true);
+
+               PropertyList plist; 
+               
+               plist.add (ARDOUR::Properties::start, current->start() + internal_start);
+               plist.add (ARDOUR::Properties::length, selection_cnt);
+               plist.add (ARDOUR::Properties::name, new_name);
+               plist.add (ARDOUR::Properties::layer, 0);
+
+               boost::shared_ptr<Region> region (RegionFactory::create (current, plist));
        }
-}      
+}
 
 void
 Editor::create_region_from_selection (vector<boost::shared_ptr<Region> >& new_regions)
@@ -2741,7 +2658,7 @@ Editor::create_region_from_selection (vector<boost::shared_ptr<Region> >& new_re
 
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
-       
+
        sort_track_selection ();
 
        for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
@@ -2759,17 +2676,22 @@ Editor::create_region_from_selection (vector<boost::shared_ptr<Region> >& new_re
                }
 
                internal_start = start - current->position();
-               session->region_name (new_name, current->name(), true);
+               RegionFactory::region_name (new_name, current->name(), true);
 
-               new_regions.push_back (RegionFactory::create (current,
-                                       internal_start, end - start + 1, new_name));
+               PropertyList plist; 
+               
+               plist.add (ARDOUR::Properties::start, current->start() + internal_start);
+               plist.add (ARDOUR::Properties::length, end - start + 1);
+               plist.add (ARDOUR::Properties::name, new_name);
+
+               new_regions.push_back (RegionFactory::create (current, plist));
        }
 }
 
 void
 Editor::split_multichannel_region ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -2780,7 +2702,7 @@ Editor::split_multichannel_region ()
        vector< boost::shared_ptr<Region> > v;
 
        for (list<RegionView*>::iterator x = rs.begin(); x != rs.end(); ++x) {
-               (*x)->region()->separate_by_channel (*session, v);
+               (*x)->region()->separate_by_channel (*_session, v);
        }
 }
 
@@ -2802,41 +2724,52 @@ add_if_covered (RegionView* rv, const AudioRange* ar, RegionSelection* rs)
        }
 }
 
-void
-Editor::separate_regions_between (const TimeSelection& ts)
+/** Return either:
+ *    - selected tracks, or if there are none...
+ *    - tracks containing selected regions, or if there are none...
+ *    - all tracks
+ * @return tracks.
+ */
+TrackViewList
+Editor::get_tracks_for_range_action () const
 {
-       bool in_command = false;
-       boost::shared_ptr<Playlist> playlist;
-       RegionSelection new_selection;
-       TrackSelection tmptracks;
+       TrackViewList t;
 
        if (selection->tracks.empty()) {
-               
-               /* use tracks with selected regions */
 
-               RegionSelection rs; 
+               /* use tracks with selected regions */
 
-               get_regions_for_action (rs);
+               RegionSelection rs = selection->regions;
 
                for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                        TimeAxisView* tv = &(*i)->get_time_axis_view();
 
-                       if (find (tmptracks.begin(), tmptracks.end(), tv) == tmptracks.end()) {
-                               tmptracks.push_back (tv);
+                       if (!t.contains (tv)) {
+                               t.push_back (tv);
                        }
                }
 
-               if (tmptracks.empty()) {
-                       /* no regions selected: do nothing */
-                       return;
+               if (t.empty()) {
+                       /* no regions and no tracks: use all tracks */
+                       t = track_views;
                }
 
        } else {
 
-               tmptracks = selection->tracks;
-
+               t = selection->tracks;
        }
 
+       return t;
+}
+
+void
+Editor::separate_regions_between (const TimeSelection& ts)
+{
+       bool in_command = false;
+       boost::shared_ptr<Playlist> playlist;
+       RegionSelection new_selection;
+
+       TrackViewList tmptracks = get_tracks_for_range_action ();
        sort_track_selection (&tmptracks);
 
        for (TrackSelection::iterator i = tmptracks.begin(); i != tmptracks.end(); ++i) {
@@ -2849,27 +2782,23 @@ Editor::separate_regions_between (const TimeSelection& ts)
 
                                /* no edits to destructive tracks */
 
-                               if (rtv->track()->diskstream()->destructive()) {
+                               if (rtv->track()->destructive()) {
                                        continue;
                                }
-                                       
-                               if ((playlist = rtv->playlist()) != 0) {
 
-                                       XMLNode *before;
-                                       bool got_some;
+                               if ((playlist = rtv->playlist()) != 0) {
 
-                                       before = &(playlist->get_state());
-                                       got_some = false;
+                                       playlist->clear_history ();
 
                                        /* XXX need to consider musical time selections here at some point */
 
-                                       double speed = rtv->get_diskstream()->speed();
+                                       double speed = rtv->track()->speed();
 
 
                                        for (list<AudioRange>::const_iterator t = ts.begin(); t != ts.end(); ++t) {
 
                                                sigc::connection c = rtv->view()->RegionViewAdded.connect (
-                                                               mem_fun(*this, &Editor::collect_new_region_view));
+                                                               sigc::mem_fun(*this, &Editor::collect_new_region_view));
                                                latest_regionviews.clear ();
 
                                                playlist->partition ((nframes64_t)((*t).start * speed),
@@ -2878,25 +2807,18 @@ Editor::separate_regions_between (const TimeSelection& ts)
                                                c.disconnect ();
 
                                                if (!latest_regionviews.empty()) {
-                                                       
-                                                       got_some = true;
 
-                                                       rtv->view()->foreach_regionview (bind (
+                                                       rtv->view()->foreach_regionview (sigc::bind (
                                                                                sigc::ptr_fun (add_if_covered),
                                                                                &(*t), &new_selection));
-                                                       
+                                                        
                                                        if (!in_command) {
                                                                begin_reversible_command (_("separate"));
                                                                in_command = true;
                                                        }
-                                                       
-                                                       session->add_command(new MementoCommand<Playlist>(
-                                                                       *playlist, before, &playlist->get_state()));
-                                               } 
-                                       }
 
-                                       if (!got_some) {
-                                               delete before;
+                                                       _session->add_command(new StatefulDiffCommand (playlist));
+                                               }
                                        }
                                }
                        }
@@ -2911,6 +2833,10 @@ Editor::separate_regions_between (const TimeSelection& ts)
        }
 }
 
+/** Take tracks from get_tracks_for_range_action and cut any regions
+ *  on those tracks so that the tracks are empty over the time
+ *  selection.
+ */
 void
 Editor::separate_region_from_selection ()
 {
@@ -2927,9 +2853,9 @@ Editor::separate_region_from_selection ()
 
                nframes64_t start;
                nframes64_t end;
-               
+
                if (get_edit_op_range (start, end)) {
-                       
+
                        AudioRange ar (start, end, 1);
                        TimeSelection ts;
                        ts.push_back (ar);
@@ -2942,7 +2868,7 @@ Editor::separate_region_from_selection ()
 void
 Editor::separate_region_from_punch ()
 {
-       Location* loc  = session->locations()->auto_punch_location();
+       Location* loc  = _session->locations()->auto_punch_location();
        if (loc) {
                separate_regions_using_location (*loc);
        }
@@ -2951,7 +2877,7 @@ Editor::separate_region_from_punch ()
 void
 Editor::separate_region_from_loop ()
 {
-       Location* loc  = session->locations()->auto_loop_location();
+       Location* loc  = _session->locations()->auto_loop_location();
        if (loc) {
                separate_regions_using_location (*loc);
        }
@@ -2988,15 +2914,15 @@ Editor::crop_region_to_selection ()
                        crop_region_to (start, end);
                }
        }
-               
-}              
+
+}
 
 void
 Editor::crop_region_to (nframes64_t start, nframes64_t end)
 {
        vector<boost::shared_ptr<Playlist> > playlists;
        boost::shared_ptr<Playlist> playlist;
-       TrackSelection* ts;
+       TrackViewList* ts;
 
        if (selection->tracks.empty()) {
                ts = &track_views;
@@ -3004,17 +2930,17 @@ Editor::crop_region_to (nframes64_t start, nframes64_t end)
                sort_track_selection ();
                ts = &selection->tracks;
        }
-       
+
        for (TrackSelection::iterator i = ts->begin(); i != ts->end(); ++i) {
-               
+
                RouteTimeAxisView* rtv;
-               
+
                if ((rtv = dynamic_cast<RouteTimeAxisView*> ((*i))) != 0) {
 
                        boost::shared_ptr<Track> t = rtv->track();
 
-                       if (t != 0 && ! t->diskstream()->destructive()) {
-                               
+                       if (t != 0 && ! t->destructive()) {
+
                                if ((playlist = rtv->playlist()) != 0) {
                                        playlists.push_back (playlist);
                                }
@@ -3025,27 +2951,27 @@ Editor::crop_region_to (nframes64_t start, nframes64_t end)
        if (playlists.empty()) {
                return;
        }
-               
+
        nframes64_t the_start;
        nframes64_t the_end;
        nframes64_t cnt;
-       
+
        begin_reversible_command (_("trim to selection"));
-       
+
        for (vector<boost::shared_ptr<Playlist> >::iterator i = playlists.begin(); i != playlists.end(); ++i) {
-               
+
                boost::shared_ptr<Region> region;
-       
+
                the_start = start;
-       
+
                if ((region = (*i)->top_region_at(the_start)) == 0) {
                        continue;
                }
-               
+
                /* now adjust lengths to that we do the right thing
                   if the selection extends beyond the region
                */
-               
+
                the_start = max (the_start, (nframes64_t) region->position());
                if (max_frames - the_start < region->length()) {
                        the_end = the_start + region->length() - 1;
@@ -3054,39 +2980,34 @@ Editor::crop_region_to (nframes64_t start, nframes64_t end)
                }
                the_end = min (end, the_end);
                cnt = the_end - the_start + 1;
-               
-               XMLNode &before = (*i)->get_state();
+
+                region->clear_history ();
                region->trim_to (the_start, cnt, this);
-               XMLNode &after = (*i)->get_state();
-               session->add_command (new MementoCommand<Playlist>(*(*i), &before, &after));
+               _session->add_command (new StatefulDiffCommand (region));
        }
-       
+
        commit_reversible_command ();
-}              
+}
 
 void
 Editor::region_fill_track ()
 {
        nframes64_t end;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
-       if (!session || rs.empty()) {
+       if (!_session || rs.empty()) {
                return;
        }
 
-       end = session->current_end_frame ();
+       end = _session->current_end_frame ();
 
        begin_reversible_command (_("region fill"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
 
                boost::shared_ptr<Region> region ((*i)->region());
-               
-               // FIXME
-               boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion>(region);
-               assert(ar);
 
                boost::shared_ptr<Playlist> pl = region->playlist();
 
@@ -3100,9 +3021,9 @@ Editor::region_fill_track ()
                        return;
                }
 
-               XMLNode &before = pl->get_state();
-               pl->add_region (RegionFactory::create (ar), ar->last_frame(), times);
-               session->add_command (new MementoCommand<Playlist>(*pl, &before, &pl->get_state()));
+                pl->clear_history ();
+               pl->add_region (RegionFactory::create (region), region->last_frame(), times);
+               _session->add_command (new StatefulDiffCommand (pl));
        }
 
        commit_reversible_command ();
@@ -3111,7 +3032,7 @@ Editor::region_fill_track ()
 void
 Editor::region_fill_selection ()
 {
-       if (clicked_routeview == 0 || !clicked_routeview->is_audio_track()) {
+       if (clicked_routeview == 0 || !clicked_routeview->is_audio_track()) {
                return;
        }
 
@@ -3119,20 +3040,15 @@ Editor::region_fill_selection ()
                return;
        }
 
-
-       Glib::RefPtr<TreeSelection> selected = region_list_display.get_selection();
-
-       if (selected->count_selected_rows() != 1) {
+       boost::shared_ptr<Region> region = _regions->get_single_selection ();
+       if (region == 0) {
                return;
        }
 
-       TreeModel::iterator i = region_list_display.get_selection()->get_selected();
-       boost::shared_ptr<Region> region = (*i)[region_list_columns.region];
-
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
 
-       boost::shared_ptr<Playlist> playlist; 
+       boost::shared_ptr<Playlist> playlist;
 
        if (selection->tracks.empty()) {
                return;
@@ -3140,21 +3056,21 @@ Editor::region_fill_selection ()
 
        nframes64_t selection_length = end - start;
        float times = (float)selection_length / region->length();
-       
+
        begin_reversible_command (_("fill selection"));
-       
+
        for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
 
                if ((playlist = (*i)->playlist()) == 0) {
                        continue;
-               }               
-               
-                XMLNode &before = playlist->get_state();
+               }
+
+                playlist->clear_history ();
                playlist->add_region (RegionFactory::create (region), start, times);
-               session->add_command (new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
+               _session->add_command (new StatefulDiffCommand (playlist));
        }
-       
-       commit_reversible_command ();                   
+
+       commit_reversible_command ();
 }
 
 void
@@ -3172,7 +3088,7 @@ Editor::set_sync_point (nframes64_t where, const RegionSelection& rs)
        bool in_command = false;
 
        for (RegionSelection::const_iterator r = rs.begin(); r != rs.end(); ++r) {
-               
+
                if (!(*r)->region()->covers (where)) {
                        continue;
                }
@@ -3184,10 +3100,9 @@ Editor::set_sync_point (nframes64_t where, const RegionSelection& rs)
                        in_command = true;
                }
 
-               XMLNode &before = region->playlist()->get_state();
-               region->set_sync_position (get_preferred_edit_position());
-               XMLNode &after = region->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(*(region->playlist()), &before, &after));
+                region->clear_history ();
+               region->set_sync_position (where);
+               _session->add_command(new StatefulDiffCommand (region));
        }
 
        if (in_command) {
@@ -3199,7 +3114,7 @@ Editor::set_sync_point (nframes64_t where, const RegionSelection& rs)
 void
 Editor::remove_region_sync ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -3210,10 +3125,9 @@ Editor::remove_region_sync ()
        begin_reversible_command (_("remove sync"));
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
 
-                XMLNode &before = (*i)->region()->playlist()->get_state();
+                (*i)->region()->clear_history ();
                (*i)->region()->clear_sync_position ();
-                XMLNode &after = (*i)->region()->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(*((*i)->region()->playlist()), &before, &after));
+               _session->add_command(new StatefulDiffCommand ((*i)->region()));
        }
        commit_reversible_command ();
 }
@@ -3221,7 +3135,7 @@ Editor::remove_region_sync ()
 void
 Editor::naturalize ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -3231,10 +3145,9 @@ Editor::naturalize ()
 
        begin_reversible_command (_("naturalize"));
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
-                XMLNode &before = (*i)->region()->get_state();
+               (*i)->region()->clear_history ();
                (*i)->region()->move_to_natural_position (this);
-                XMLNode &after = (*i)->region()->get_state();
-               session->add_command (new MementoCommand<Region>(*((*i)->region().get()), &before, &after));
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
        commit_reversible_command ();
 }
@@ -3242,7 +3155,7 @@ Editor::naturalize ()
 void
 Editor::align (RegionPoint what)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
        nframes64_t where = get_preferred_edit_position();
@@ -3261,13 +3174,13 @@ void
 Editor::align_relative (RegionPoint what)
 {
        nframes64_t where = get_preferred_edit_position();
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
        if (!rs.empty()) {
                align_selection_relative (what, where, rs);
-       } 
+       }
 }
 
 struct RegionSortByTime {
@@ -3302,7 +3215,7 @@ Editor::align_selection_relative (RegionPoint point, nframes64_t position, const
                        dir = -1;
                }
                break;
-               
+
        case End:
                if (position > r->last_frame()) {
                        distance = position - r->last_frame();
@@ -3322,7 +3235,7 @@ Editor::align_selection_relative (RegionPoint point, nframes64_t position, const
                        distance = r->position() - pos;
                        dir = -1;
                }
-               break;  
+               break;
        }
 
        if (pos == r->position()) {
@@ -3333,29 +3246,27 @@ Editor::align_selection_relative (RegionPoint point, nframes64_t position, const
 
        /* move first one specially */
 
-       XMLNode &before = r->playlist()->get_state();
+        r->clear_history ();
        r->set_position (pos, this);
-       XMLNode &after = r->playlist()->get_state();
-       session->add_command(new MementoCommand<Playlist>(*(r->playlist()), &before, &after));
+       _session->add_command(new StatefulDiffCommand (r));
 
        /* move rest by the same amount */
-       
+
        sorted.pop_front();
-       
+
        for (list<RegionView*>::iterator i = sorted.begin(); i != sorted.end(); ++i) {
 
                boost::shared_ptr<Region> region ((*i)->region());
 
-                XMLNode &before = region->playlist()->get_state();
-               
+                region->clear_history ();
+
                if (dir > 0) {
                        region->set_position (region->position() + distance, this);
                } else {
                        region->set_position (region->position() - distance, this);
                }
-
-                XMLNode &after = region->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(*(region->playlist()), &before, &after));
+                
+               _session->add_command(new StatefulDiffCommand (region));
 
        }
 
@@ -3389,7 +3300,7 @@ Editor::align_region (boost::shared_ptr<Region> region, RegionPoint point, nfram
 void
 Editor::align_region_internal (boost::shared_ptr<Region> region, RegionPoint point, nframes64_t position)
 {
-       XMLNode &before = region->playlist()->get_state();
+       region->clear_history ();
 
        switch (point) {
        case SyncPoint:
@@ -3407,9 +3318,8 @@ Editor::align_region_internal (boost::shared_ptr<Region> region, RegionPoint poi
                break;
        }
 
-       XMLNode &after = region->playlist()->get_state();
-       session->add_command(new MementoCommand<Playlist>(*(region->playlist()), &before, &after));
-}      
+       _session->add_command(new StatefulDiffCommand (region));
+}
 
 void
 Editor::trim_region_front ()
@@ -3439,15 +3349,13 @@ Editor::trim_region (bool front)
 
        for (list<RegionView*>::const_iterator i = rs.by_layer().begin(); i != rs.by_layer().end(); ++i) {
                if (!(*i)->region()->locked()) {
-                       boost::shared_ptr<Playlist> pl = (*i)->region()->playlist();
-                       XMLNode &before = pl->get_state();
+                        (*i)->region()->clear_history ();
                        if (front) {
-                               (*i)->region()->trim_front (where, this);       
+                               (*i)->region()->trim_front (where, this);
                        } else {
-                               (*i)->region()->trim_end (where, this); 
+                               (*i)->region()->trim_end (where, this);
                        }
-                       XMLNode &after = pl->get_state();
-                       session->add_command(new MementoCommand<Playlist>(*pl.get(), &before, &after));
+                       _session->add_command (new StatefulDiffCommand ((*i)->region()));
                }
        }
 
@@ -3458,7 +3366,7 @@ Editor::trim_region (bool front)
 void
 Editor::trim_region_to_loop ()
 {
-       Location* loc = session->locations()->auto_loop_location();
+       Location* loc = _session->locations()->auto_loop_location();
        if (!loc) {
                return;
        }
@@ -3468,7 +3376,7 @@ Editor::trim_region_to_loop ()
 void
 Editor::trim_region_to_punch ()
 {
-       Location* loc = session->locations()->auto_punch_location();
+       Location* loc = _session->locations()->auto_punch_location();
        if (!loc) {
                return;
        }
@@ -3493,7 +3401,7 @@ Editor::trim_region_to_location (const Location& loc, const char* str)
                default:
                        continue;
                }
-                               
+
                RouteTimeAxisView* tav = dynamic_cast<RouteTimeAxisView*> (&rv->get_time_axis_view());
                if (!tav) {
                        return;
@@ -3503,18 +3411,16 @@ Editor::trim_region_to_location (const Location& loc, const char* str)
                nframes64_t start;
                nframes64_t end;
 
-               if (tav->get_diskstream() != 0) {
-                       speed = tav->get_diskstream()->speed();
+               if (tav->track() != 0) {
+                       speed = tav->track()->speed();
                }
-               
+
                start = session_frame_to_track_frame (loc.start(), speed);
                end = session_frame_to_track_frame (loc.end(), speed);
-
-               XMLNode &before = rv->region()->playlist()->get_state();
+                
+               rv->region()->clear_history ();
                rv->region()->trim_to (start, (end - start), this);
-               XMLNode &after = rv->region()->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(
-                               *(rv->region()->playlist()), &before, &after));
+               _session->add_command(new StatefulDiffCommand (rv->region()));
        }
 
        commit_reversible_command ();
@@ -3524,7 +3430,7 @@ void
 Editor::trim_region_to_edit_point ()
 {
        RegionSelection rs;
-       
+
        get_regions_for_action (rs);
 
        nframes64_t where = get_preferred_edit_position();
@@ -3546,17 +3452,15 @@ Editor::trim_region_to_edit_point ()
 
                float speed = 1.0;
 
-               if (tav->get_diskstream() != 0) {
-                       speed = tav->get_diskstream()->speed();
+               if (tav->track() != 0) {
+                       speed = tav->track()->speed();
                }
 
-               XMLNode &before = rv->region()->playlist()->get_state();
-               rv->region()->trim_end( session_frame_to_track_frame(where, speed), this);
-               XMLNode &after = rv->region()->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(
-                               *(rv->region()->playlist()), &before, &after));
+                rv->region()->clear_history ();
+               rv->region()->trim_end (session_frame_to_track_frame(where, speed), this);
+               _session->add_command(new StatefulDiffCommand (rv->region()));
        }
-               
+
        commit_reversible_command ();
 }
 
@@ -3586,17 +3490,15 @@ Editor::trim_region_from_edit_point ()
 
                float speed = 1.0;
 
-               if (tav->get_diskstream() != 0) {
-                       speed = tav->get_diskstream()->speed();
+               if (tav->track() != 0) {
+                       speed = tav->track()->speed();
                }
 
-               XMLNode &before = rv->region()->playlist()->get_state();
-               rv->region()->trim_front ( session_frame_to_track_frame(where, speed), this);
-               XMLNode &after = rv->region()->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(
-                               *(rv->region()->playlist()), &before, &after));
+                rv->region()->clear_history ();
+               rv->region()->trim_front (session_frame_to_track_frame(where, speed), this);
+               _session->add_command(new StatefulDiffCommand (rv->region()));
        }
-               
+
        commit_reversible_command ();
 }
 
@@ -3639,15 +3541,15 @@ Editor::trim_to_region(bool forward)
 
                float speed = 1.0;
 
-               if (atav->get_diskstream() != 0) {
-                       speed = atav->get_diskstream()->speed();
+               if (atav->track() != 0) {
+                       speed = atav->track()->speed();
                }
 
-               
+
                boost::shared_ptr<Region> region = arv->region();
                boost::shared_ptr<Playlist> playlist (region->playlist());
-               
-               XMLNode &before = playlist->get_state();
+
+                region->clear_history ();
 
                if(forward){
 
@@ -3658,7 +3560,7 @@ Editor::trim_to_region(bool forward)
                    }
 
                    region->trim_end((nframes64_t) (next_region->first_frame() * speed), this);
-                   arv->region_changed (Change (LengthChanged));
+                   arv->region_changed (PropertyChange (ARDOUR::Properties::length));
                }
                else {
 
@@ -3668,12 +3570,12 @@ Editor::trim_to_region(bool forward)
                        continue;
                    }
 
-                   region->trim_front((nframes64_t) ((next_region->last_frame() + 1) * speed), this);              
-                   arv->region_changed (Change (LengthChanged|PositionChanged|StartChanged));
+                   region->trim_front((nframes64_t) ((next_region->last_frame() + 1) * speed), this);
+
+                   arv->region_changed (ARDOUR::bounds_change);
                }
 
-               XMLNode &after = playlist->get_state();
-               session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
+               _session->add_command(new StatefulDiffCommand (region));
        }
 
        commit_reversible_command ();
@@ -3685,69 +3587,43 @@ Editor::unfreeze_route ()
        if (clicked_routeview == 0 || !clicked_routeview->is_track()) {
                return;
        }
-       
+
        clicked_routeview->track()->unfreeze ();
 }
 
 void*
 Editor::_freeze_thread (void* arg)
 {
-       PBD::notify_gui_about_thread_creation (pthread_self(), X_("Freeze"));
+       SessionEvent::create_per_thread_pool ("freeze events", 64);
+
        return static_cast<Editor*>(arg)->freeze_thread ();
 }
 
 void*
 Editor::freeze_thread ()
 {
-       clicked_routeview->audio_track()->freeze (*current_interthread_info);
+       clicked_routeview->audio_track()->freeze_me (*current_interthread_info);
        current_interthread_info->done = true;
        return 0;
 }
 
-gint
-Editor::freeze_progress_timeout (void *arg)
-{
-       interthread_progress_bar.set_fraction (current_interthread_info->progress);
-       return !(current_interthread_info->done || current_interthread_info->cancel);
-}
-
 void
 Editor::freeze_route ()
 {
        if (clicked_routeview == 0 || !clicked_routeview->is_audio_track()) {
                return;
        }
-       
-       InterThreadInfo itt;
-
-       if (interthread_progress_window == 0) {
-               build_interthread_progress_window ();
-       }
 
-       WindowTitle title(Glib::get_application_name());
-       title += _("Freeze");
-       interthread_progress_window->set_title (title.get_string());
-       interthread_progress_window->set_position (Gtk::WIN_POS_MOUSE);
-       interthread_progress_window->show_all ();
-       interthread_progress_bar.set_fraction (0.0f);
-       interthread_progress_label.set_text ("");
-       interthread_cancel_label.set_text (_("Cancel Freeze"));
+       InterThreadInfo itt;
        current_interthread_info = &itt;
 
-       interthread_progress_connection = 
-         Glib::signal_timeout().connect (bind (mem_fun(*this, &Editor::freeze_progress_timeout), (gpointer) 0), 100);
+       InterthreadProgressWindow ipw (current_interthread_info, _("Freeze"), _("Cancel Freeze"));
 
        itt.done = false;
        itt.cancel = false;
        itt.progress = 0.0f;
-       
-       pthread_attr_t attr;
-       pthread_attr_init(&attr);
-       pthread_attr_setstacksize(&attr, 500000);
-
-       pthread_create_and_store (X_("freezer"), &itt.thread, &attr, _freeze_thread, this);
 
-       pthread_attr_destroy(&attr);
+       pthread_create_and_store (X_("freezer"), &itt.thread, _freeze_thread, this);
 
        track_canvas->get_window()->set_cursor (Gdk::Cursor (Gdk::WATCH));
 
@@ -3755,8 +3631,6 @@ Editor::freeze_route ()
                gtk_main_iteration ();
        }
 
-       interthread_progress_connection.disconnect ();
-       interthread_progress_window->hide_all ();
        current_interthread_info = 0;
        track_canvas->get_window()->set_cursor (*current_canvas_cursor);
 }
@@ -3783,22 +3657,22 @@ Editor::bounce_range_selection (bool replace, bool enable_processing)
                if ((rtv = dynamic_cast<RouteTimeAxisView*> (*i)) == 0) {
                        continue;
                }
-               
+
                boost::shared_ptr<Playlist> playlist;
-               
+
                if ((playlist = rtv->playlist()) == 0) {
                        return;
                }
 
                InterThreadInfo itt;
-               
+
                itt.done = false;
                itt.cancel = false;
                itt.progress = false;
 
-                XMLNode &before = playlist->get_state();
+                playlist->clear_history ();
                boost::shared_ptr<Region> r = rtv->track()->bounce_range (start, start+cnt, itt, enable_processing);
-               
+
                if (replace) {
                        list<AudioRange> ranges;
                        ranges.push_back (AudioRange (start, start+cnt, 0));
@@ -3806,10 +3680,9 @@ Editor::bounce_range_selection (bool replace, bool enable_processing)
                        playlist->add_region (r, start);
                }
 
-                XMLNode &after = playlist->get_state();
-               session->add_command (new MementoCommand<Playlist> (*playlist, &before, &after));
+               _session->add_command (new StatefulDiffCommand (playlist));
        }
-       
+
        commit_reversible_command ();
 }
 
@@ -3833,19 +3706,19 @@ bool
 Editor::can_cut_copy () const
 {
        switch (current_mouse_mode()) {
-               
+
        case MouseObject:
                if (!selection->regions.empty() || !selection->points.empty()) {
                        return true;
                }
                break;
-               
+
        case MouseRange:
                if (!selection->time.empty()) {
                        return true;
                }
                break;
-               
+
        default:
                break;
        }
@@ -3857,7 +3730,7 @@ Editor::can_cut_copy () const
 /** Cut, copy or clear selected regions, automation points or a time range.
  * @param op Operation (Cut, Copy or Clear)
  */
-void 
+void
 Editor::cut_copy (CutCopyOp op)
 {
        /* only cancel selection if cut/copy is successful.*/
@@ -3883,13 +3756,11 @@ Editor::cut_copy (CutCopyOp op)
        */
 
        if (op == Cut || op == Clear) {
-               if (_drag) {
-                       _drag->item()->ungrab (0);
-                       delete _drag;
-                       _drag = 0;
+               if (_drags->active ()) {
+                       _drags->abort ();
                }
        }
-       
+
        cut_buffer->clear ();
 
        if (entered_marker) {
@@ -3899,84 +3770,92 @@ Editor::cut_copy (CutCopyOp op)
                bool ignored;
                Location* loc = find_location_from_marker (entered_marker, ignored);
 
-               if (session && loc) {
-                       Glib::signal_idle().connect (bind (mem_fun(*this, &Editor::really_remove_marker), loc));
+               if (_session && loc) {
+                       Glib::signal_idle().connect (sigc::bind (sigc::mem_fun(*this, &Editor::really_remove_marker), loc));
                }
 
-               break_drag ();
-               delete _drag;
-               _drag = 0;
-
+               _drags->break_drag ();
                return;
        }
 
-       RegionSelection rs; 
+       if (internal_editing()) {
 
-       /* we only want to cut regions if some are selected */
+               switch (current_mouse_mode()) {
+               case MouseObject:
+               case MouseRange:
+                       cut_copy_midi (op);
+                       break;
+               default:
+                       break;
+               }
 
-       if (!selection->regions.empty()) {
-               get_regions_for_action (rs);
-       }
+       } else {
 
-       switch (current_mouse_mode()) {
-       case MouseObject: 
-               if (!rs.empty() || !selection->points.empty()) {
+               RegionSelection rs;
+
+               /* we only want to cut regions if some are selected */
 
-                       begin_reversible_command (opname + _(" objects"));
+               if (!selection->regions.empty()) {
+                       get_regions_for_action (rs, false, false);
+               }
 
-                       if (!rs.empty()) {
-                               cut_copy_regions (op, rs);
-                               
-                               if (op == Cut) {
-                                       selection->clear_regions ();
+               switch (current_mouse_mode()) {
+               case MouseObject:
+                       if (!rs.empty() || !selection->points.empty()) {
+
+                               begin_reversible_command (opname + _(" objects"));
+
+                               if (!rs.empty()) {
+                                       cut_copy_regions (op, rs);
+
+                                       if (op == Cut) {
+                                               selection->clear_regions ();
+                                       }
                                }
-                       }
 
-                       if (!selection->points.empty()) {
-                               cut_copy_points (op);
+                               if (!selection->points.empty()) {
+                                       cut_copy_points (op);
 
-                               if (op == Cut) {
-                                       selection->clear_points ();
+                                       if (op == Cut) {
+                                               selection->clear_points ();
+                                       }
                                }
+
+                               commit_reversible_command ();
+                               break; // terminate case statement here
                        }
+                       if (!selection->time.empty()) {
+                               /* don't cause suprises */
+                               break;
+                       }
+                       // fall thru if there was nothing selected
 
-                       commit_reversible_command ();   
-                       break; // terminate case statement here
-               } 
-               if (!selection->time.empty()) {
-                       /* don't cause suprises */
-                       break;
-               }
-               // fall thru if there was nothing selected
-               
-       case MouseRange:
-               if (selection->time.empty()) {
-                       nframes64_t start, end;
-                       if (!get_edit_op_range (start, end)) {
-                               return;
+               case MouseRange:
+                       if (selection->time.empty()) {
+                               nframes64_t start, end;
+                               if (!get_edit_op_range (start, end)) {
+                                       return;
+                               }
+                               selection->set (start, end);
                        }
-                       selection->set ((TimeAxisView*) 0, start, end);
-               }
-                       
-               begin_reversible_command (opname + _(" range"));
-               cut_copy_ranges (op);
-               commit_reversible_command ();
-               
-               if (op == Cut) {
-                       selection->clear_time ();
-               }
 
-               break;
-               
-       default:
-               break;
-       }
+                       begin_reversible_command (opname + _(" range"));
+                       cut_copy_ranges (op);
+                       commit_reversible_command ();
+
+                       if (op == Cut) {
+                               selection->clear_time ();
+                       }
+
+                       break;
 
+               default:
+                       break;
+               }
+       }
 
        if (op == Cut || op == Clear) {
-               break_drag ();
-               delete _drag;
-               _drag = 0;
+               _drags->break_drag ();
        }
 }
 
@@ -3988,26 +3867,27 @@ Editor::cut_copy_points (CutCopyOp op)
 {
        for (PointSelection::iterator i = selection->points.begin(); i != selection->points.end(); ++i) {
 
-               AutomationTimeAxisView* atv = dynamic_cast<AutomationTimeAxisView*>(&(*i).track);
+               AutomationTimeAxisView* atv = dynamic_cast<AutomationTimeAxisView*>((*i).track);
 
                if (atv) {
                        atv->cut_copy_clear_objects (selection->points, op);
-               } 
+               }
        }
 }
 
-struct PlaylistState {
-    boost::shared_ptr<Playlist> playlist;
-    XMLNode*  before;
-};
+/** Cut, copy or clear selected automation points.
+ * @param op Operation (Cut, Copy or Clear)
+ */
+void
+Editor::cut_copy_midi (CutCopyOp op)
+{
+       for (MidiRegionSelection::iterator i = selection->midi_regions.begin(); i != selection->midi_regions.end(); ++i) {
+               MidiRegionView* mrv = *i;
+               mrv->cut_copy_clear (op);
+       }
+}
 
-struct lt_playlist {
-    bool operator () (const PlaylistState& a, const PlaylistState& b) {
-           return a.playlist < b.playlist;
-    }
-};
-       
-struct PlaylistMapping { 
+struct PlaylistMapping {
     TimeAxisView* tv;
     boost::shared_ptr<Playlist> pl;
 
@@ -4023,12 +3903,11 @@ Editor::remove_clicked_region ()
        }
 
        boost::shared_ptr<Playlist> playlist = clicked_routeview->playlist();
-       
+
        begin_reversible_command (_("remove region"));
-        XMLNode &before = playlist->get_state();
+        playlist->clear_history ();
        playlist->remove_region (clicked_regionview->region());
-        XMLNode &after = playlist->get_state();
-       session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
+       _session->add_command(new StatefulDiffCommand (playlist));
        commit_reversible_command ();
 }
 
@@ -4037,10 +3916,10 @@ Editor::remove_clicked_region ()
 void
 Editor::remove_selected_regions ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
        get_regions_for_action (rs);
-       
-       if (!session) {
+
+       if (!_session) {
                return;
        }
 
@@ -4061,12 +3940,12 @@ Editor::remove_selected_regions ()
                // so, first iterate over the regions to be removed from rs and
                // add them to the regions_to_remove list, and then
                // iterate over the list to actually remove them.
-               
+
                regions_to_remove.push_back ((*i)->region());
        }
 
-       vector<PlaylistState> playlists;
-       
+        vector<boost::shared_ptr<Playlist> > playlists;
+
        for (list<boost::shared_ptr<Region> >::iterator rl = regions_to_remove.begin(); rl != regions_to_remove.end(); ++rl) {
 
                boost::shared_ptr<Playlist> playlist = (*rl)->playlist();
@@ -4076,33 +3955,31 @@ Editor::remove_selected_regions ()
                        continue;
                }
 
-               vector<PlaylistState>::iterator i;
+               vector<boost::shared_ptr<Playlist> >::iterator i;
 
-               //only take state if this is a new playlist.
+               //only prep history if this is a new playlist.
                for (i = playlists.begin(); i != playlists.end(); ++i) {
-                       if ((*i).playlist == playlist) {
+                       if ((*i) == playlist) {
                                break;
                        }
                }
 
                if (i == playlists.end()) {
 
-                       PlaylistState before;
-                       before.playlist = playlist;
-                       before.before = &playlist->get_state();
-
+                        playlist->clear_history ();
                        playlist->freeze ();
-                       playlists.push_back(before);
+
+                       playlists.push_back (playlist);
                }
 
-               playlist->remove_region (*rl);          
+               playlist->remove_region (*rl);
        }
 
-       vector<PlaylistState>::iterator pl;
+       vector<boost::shared_ptr<Playlist> >::iterator pl;
 
        for (pl = playlists.begin(); pl != playlists.end(); ++pl) {
-               (*pl).playlist->thaw ();
-               session->add_command(new MementoCommand<Playlist>(*(*pl).playlist, (*pl).before, &(*pl).playlist->get_state()));
+               (*pl)->thaw ();
+               _session->add_command(new StatefulDiffCommand (*pl));
        }
 
        commit_reversible_command ();
@@ -4121,12 +3998,12 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
        vector<PlaylistMapping> pmap;
 
        nframes64_t first_position = max_frames;
-       
-       set<PlaylistState, lt_playlist> freezelist;
-       pair<set<PlaylistState, lt_playlist>::iterator,bool> insert_result;
-       
+
+       typedef set<boost::shared_ptr<Playlist> > FreezeList;
+        FreezeList freezelist;
+
        /* get ordering correct before we cut/copy */
-       
+
        rs.sort_by_position_and_track ();
 
        for (RegionSelection::iterator x = rs.begin(); x != rs.end(); ++x) {
@@ -4137,21 +4014,19 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
                        boost::shared_ptr<Playlist> pl = (*x)->region()->playlist();
 
                        if (pl) {
-                               set<PlaylistState, lt_playlist>::iterator fl;
+                               FreezeList::iterator fl;
 
                                //only take state if this is a new playlist.
                                for (fl = freezelist.begin(); fl != freezelist.end(); ++fl) {
-                                       if ((*fl).playlist == pl) {
+                                       if ((*fl) == pl) {
                                                break;
                                        }
                                }
-               
+
                                if (fl == freezelist.end()) {
-                                       PlaylistState before;
-                                       before.playlist = pl;
-                                       before.before = &pl->get_state();
+                                        pl->clear_history();
                                        pl->freeze ();
-                                       insert_result = freezelist.insert (before);
+                                       freezelist.insert (pl);
                                }
                        }
                }
@@ -4164,7 +4039,7 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
                                break;
                        }
                }
-               
+
                if (z == pmap.end()) {
                        pmap.push_back (PlaylistMapping (tv));
                }
@@ -4173,7 +4048,7 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
        for (RegionSelection::iterator x = rs.begin(); x != rs.end(); ) {
 
                boost::shared_ptr<Playlist> pl = (*x)->region()->playlist();
-               
+
                if (!pl) {
                        /* impossible, but this handles it for the future */
                        continue;
@@ -4182,28 +4057,28 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
                TimeAxisView& tv = (*x)->get_trackview();
                boost::shared_ptr<Playlist> npl;
                RegionSelection::iterator tmp;
-               
+
                tmp = x;
                ++tmp;
 
                vector<PlaylistMapping>::iterator z;
-               
+
                for (z = pmap.begin(); z != pmap.end(); ++z) {
                        if ((*z).tv == &tv) {
                                break;
                        }
                }
-               
+
                assert (z != pmap.end());
-               
+
                if (!(*z).pl) {
-                       npl = PlaylistFactory::create (pl->data_type(), *session, "cutlist", true);
+                       npl = PlaylistFactory::create (pl->data_type(), *_session, "cutlist", true);
                        npl->freeze();
                        (*z).pl = npl;
                } else {
                        npl = (*z).pl;
                }
-               
+
                boost::shared_ptr<Region> r = (*x)->region();
                boost::shared_ptr<Region> _xx;
 
@@ -4215,12 +4090,12 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
                        npl->add_region (_xx, r->position() - first_position);
                        pl->remove_region (r);
                        break;
-                       
+
                case Copy:
                        /* copy region before adding, so we're not putting same object into two different playlists */
                        npl->add_region (RegionFactory::create (r), r->position() - first_position);
                        break;
-                       
+
                case Clear:
                        pl->remove_region (r);
                        break;
@@ -4228,32 +4103,32 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
 
                x = tmp;
        }
-       
+
        list<boost::shared_ptr<Playlist> > foo;
-       
+
        /* the pmap is in the same order as the tracks in which selected regions occured */
-       
+
        for (vector<PlaylistMapping>::iterator i = pmap.begin(); i != pmap.end(); ++i) {
                (*i).pl->thaw();
                foo.push_back ((*i).pl);
        }
-       
+
 
        if (!foo.empty()) {
                cut_buffer->set (foo);
        }
-
-       for (set<PlaylistState, lt_playlist>::iterator pl = freezelist.begin(); pl != freezelist.end(); ++pl) {
-               (*pl).playlist->thaw ();
-               session->add_command (new MementoCommand<Playlist>(*(*pl).playlist, (*pl).before, &(*pl).playlist->get_state()));
+        
+       for (FreezeList::iterator pl = freezelist.begin(); pl != freezelist.end(); ++pl) {
+               (*pl)->thaw ();
+               _session->add_command (new StatefulDiffCommand (*pl));
        }
 }
 
 void
 Editor::cut_copy_ranges (CutCopyOp op)
 {
-       TrackSelection* ts;
-       TrackSelection entered;
+       TrackViewList* ts;
+       TrackViewList entered;
 
        if (selection->tracks.empty()) {
                if (!entered_track) {
@@ -4295,8 +4170,14 @@ Editor::paste_internal (nframes64_t position, float times)
 {
        bool commit = false;
 
-       if (cut_buffer->empty()) {
-               return;
+       if (internal_editing()) {
+               if (cut_buffer->midi_notes.empty()) {
+                       return;
+               }
+       } else {
+               if (cut_buffer->empty()) {
+                       return;
+               }
        }
 
        if (position == max_frames) {
@@ -4305,13 +4186,12 @@ Editor::paste_internal (nframes64_t position, float times)
 
        begin_reversible_command (_("paste"));
 
-       TrackSelection ts;
-       TrackSelection::iterator i;
+       TrackViewList ts;
+       TrackViewList::iterator i;
        size_t nth;
 
        /* get everything in the correct order */
 
-
        if (!selection->tracks.empty()) {
                sort_track_selection ();
                ts = selection->tracks;
@@ -4321,81 +4201,48 @@ Editor::paste_internal (nframes64_t position, float times)
 
        for (nth = 0, i = ts.begin(); i != ts.end(); ++i, ++nth) {
 
-               /* undo/redo is handled by individual tracks */
+               /* undo/redo is handled by individual tracks/regions */
 
-               if ((*i)->paste (position, times, *cut_buffer, nth)) {
-                       commit = true;
-               }
-       }
-       
-       if (commit) {
-               commit_reversible_command ();
-       }
-}
-
-void
-Editor::paste_named_selection (float times)
-{
-       TrackSelection::iterator t;
+               if (internal_editing()) {
 
-       Glib::RefPtr<TreeSelection> selected = named_selection_display.get_selection();
+                       RegionSelection rs;
+                       RegionSelection::iterator r;
+                       MidiNoteSelection::iterator cb;
 
-       if (selected->count_selected_rows() != 1 || selection->tracks.empty()) {
-               return;
-       }
+                       get_regions_at (rs, position, ts);
 
-       TreeModel::iterator i = selected->get_selected();
-       NamedSelection* ns = (*i)[named_selection_columns.selection];
-
-       list<boost::shared_ptr<Playlist> >::iterator chunk;
-       list<boost::shared_ptr<Playlist> >::iterator tmp;
-
-       chunk = ns->playlists.begin();
-               
-       begin_reversible_command (_("paste chunk"));
-       
-       sort_track_selection ();
-
-       for (t = selection->tracks.begin(); t != selection->tracks.end(); ++t) {
-               
-               RouteTimeAxisView* rtv;
-               boost::shared_ptr<Playlist> pl;
-               boost::shared_ptr<AudioPlaylist> apl;
-
-               if ((rtv = dynamic_cast<RouteTimeAxisView*> (*t)) == 0) {
-                       continue;
-               }
-
-               if ((pl = rtv->playlist()) == 0) {
-                       continue;
-               }
-               
-               if ((apl = boost::dynamic_pointer_cast<AudioPlaylist> (pl)) == 0) {
-                       continue;
-               }
-
-               tmp = chunk;
-               ++tmp;
+                       for (cb = cut_buffer->midi_notes.begin(), r = rs.begin();
+                            cb != cut_buffer->midi_notes.end() && r != rs.end(); ++r) {
+                               MidiRegionView* mrv = dynamic_cast<MidiRegionView*> (*r);
+                               if (mrv) {
+                                       mrv->paste (position, times, **cb);
+                                       ++cb;
+                               }
+                       }
 
-               XMLNode &before = apl->get_state();
-               apl->paste (*chunk, get_preferred_edit_position(), times);
-               session->add_command(new MementoCommand<AudioPlaylist>(*apl, &before, &apl->get_state()));
+               } else {
 
-               if (tmp != ns->playlists.end()) {
-                       chunk = tmp;
+                       if ((*i)->paste (position, times, *cut_buffer, nth)) {
+                               commit = true;
+                       }
                }
        }
 
-       commit_reversible_command();
+       if (commit) {
+               commit_reversible_command ();
+       }
 }
 
 void
 Editor::duplicate_some_regions (RegionSelection& regions, float times)
 {
-       boost::shared_ptr<Playlist> playlist; 
+       boost::shared_ptr<Playlist> playlist;
        RegionSelection sel = regions; // clear (below) may  clear the argument list if its the current region selection
        RegionSelection foo;
 
+       nframes_t const start_frame = regions.start ();
+       nframes_t const end_frame = regions.end_frame ();
+
        begin_reversible_command (_("duplicate region"));
 
        selection->clear_regions ();
@@ -4407,15 +4254,15 @@ Editor::duplicate_some_regions (RegionSelection& regions, float times)
                TimeAxisView& tv = (*i)->get_time_axis_view();
                RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (&tv);
                latest_regionviews.clear ();
-               sigc::connection c = rtv->view()->RegionViewAdded.connect (mem_fun(*this, &Editor::collect_new_region_view));
-               
+               sigc::connection c = rtv->view()->RegionViewAdded.connect (sigc::mem_fun(*this, &Editor::collect_new_region_view));
+
                playlist = (*i)->region()->playlist();
-                XMLNode &before = playlist->get_state();
-               playlist->duplicate (r, r->last_frame(), times);
-               session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
+                playlist->clear_history ();
+               playlist->duplicate (r, end_frame + (r->first_frame() - start_frame) + 1, times);
+               _session->add_command(new StatefulDiffCommand (playlist));
 
                c.disconnect ();
-               
+
                foo.insert (foo.end(), latest_regionviews.begin(), latest_regionviews.end());
        }
 
@@ -4433,16 +4280,16 @@ Editor::duplicate_selection (float times)
                return;
        }
 
-       boost::shared_ptr<Playlist> playlist; 
+       boost::shared_ptr<Playlist> playlist;
        vector<boost::shared_ptr<Region> > new_regions;
        vector<boost::shared_ptr<Region> >::iterator ri;
-               
+
        create_region_from_selection (new_regions);
 
        if (new_regions.empty()) {
                return;
        }
-       
+
        begin_reversible_command (_("duplicate selection"));
 
        ri = new_regions.begin();
@@ -4451,10 +4298,9 @@ Editor::duplicate_selection (float times)
                if ((playlist = (*i)->playlist()) == 0) {
                        continue;
                }
-               XMLNode &before = playlist->get_state();
+                playlist->clear_history ();
                playlist->duplicate (*ri, selection->time[clicked_selection].end, times);
-               XMLNode &after = playlist->get_state();
-               session->add_command (new MementoCommand<Playlist>(*playlist, &before, &after));
+               _session->add_command (new StatefulDiffCommand (playlist));
 
                ++ri;
                if (ri == new_regions.end()) {
@@ -4471,26 +4317,26 @@ Editor::reset_point_selection ()
        /* reset all selected points to the relevant default value */
 
        for (PointSelection::iterator i = selection->points.begin(); i != selection->points.end(); ++i) {
-               
-               AutomationTimeAxisView* atv = dynamic_cast<AutomationTimeAxisView*>(&(*i).track);
-               
+
+               AutomationTimeAxisView* atv = dynamic_cast<AutomationTimeAxisView*>((*i).track);
+
                if (atv) {
                        atv->reset_objects (selection->points);
-               } 
+               }
        }
 }
 
 void
 Editor::center_playhead ()
 {
-       float page = canvas_width * frames_per_unit;
+       float page = _canvas_width * frames_per_unit;
        center_screen_internal (playhead_cursor->current_frame, page);
 }
 
 void
 Editor::center_edit_point ()
 {
-       float page = canvas_width * frames_per_unit;
+       float page = _canvas_width * frames_per_unit;
        center_screen_internal (get_preferred_edit_position(), page);
 }
 
@@ -4498,17 +4344,16 @@ void
 Editor::clear_playlist (boost::shared_ptr<Playlist> playlist)
 {
        begin_reversible_command (_("clear playlist"));
-        XMLNode &before = playlist->get_state();
+        playlist->clear_history ();
        playlist->clear ();
-        XMLNode &after = playlist->get_state();
-       session->add_command (new MementoCommand<Playlist>(*playlist.get(), &before, &after));
+       _session->add_command (new StatefulDiffCommand (playlist));
        commit_reversible_command ();
 }
 
 void
 Editor::nudge_track (bool use_edit, bool forwards)
 {
-       boost::shared_ptr<Playlist> playlist; 
+       boost::shared_ptr<Playlist> playlist;
        nframes64_t distance;
        nframes64_t next_distance;
        nframes64_t start;
@@ -4522,26 +4367,36 @@ Editor::nudge_track (bool use_edit, bool forwards)
        if ((distance = get_nudge_distance (start, next_distance)) == 0) {
                return;
        }
-       
+
        if (selection->tracks.empty()) {
                return;
        }
-       
+
        begin_reversible_command (_("nudge track"));
-       
+
        for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
 
                if ((playlist = (*i)->playlist()) == 0) {
                        continue;
-               }               
-               
-                XMLNode &before = playlist->get_state();
+               }
+
+                playlist->clear_history ();
+                playlist->clear_owned_history ();
+
                playlist->nudge_after (start, distance, forwards);
-                XMLNode &after = playlist->get_state();
-               session->add_command (new MementoCommand<Playlist>(*playlist, &before, &after));
+                
+                vector<StatefulDiffCommand*> cmds;
+
+                playlist->rdiff (cmds);
+
+                for (vector<StatefulDiffCommand*>::iterator c = cmds.begin(); c != cmds.end(); ++c) {
+                        _session->add_command (*c);
+                }
+
+                _session->add_command (new StatefulDiffCommand (playlist));
        }
-       
-       commit_reversible_command ();                   
+
+       commit_reversible_command ();
 }
 
 void
@@ -4549,8 +4404,8 @@ Editor::remove_last_capture ()
 {
        vector<string> choices;
        string prompt;
-       
-       if (!session) {
+
+       if (!_session) {
                return;
        }
 
@@ -4560,30 +4415,48 @@ Editor::remove_last_capture ()
 
                choices.push_back (_("No, do nothing."));
                choices.push_back (_("Yes, destroy it."));
-               
-               Gtkmm2ext::Choice prompter (prompt, choices);
-               
+
+               Gtkmm2ext::Choice prompter (_("Destroy last capture"), prompt, choices);
+
                if (prompter.run () == 1) {
-                       session->remove_last_capture ();
+                       _session->remove_last_capture ();
                }
 
        } else {
-               session->remove_last_capture();
+               _session->remove_last_capture();
        }
 }
 
 void
 Editor::normalize_region ()
 {
-       RegionSelection rs; 
+       if (!_session) {
+               return;
+       }
 
+       RegionSelection rs;
        get_regions_for_action (rs);
-       
-       if (!session) {
+
+       if (rs.empty()) {
                return;
        }
 
-       if (rs.empty()) {
+       Dialog dialog (rs.size() > 1 ? _("Normalize regions") : _("Normalize region"));
+       HBox hbox;
+       hbox.pack_start (*manage (new Label (_("Normalize to:"))));
+       SpinButton spin (0.2, 2);
+       spin.set_range (-112, 0);
+       spin.set_increments (0.1, 1);
+       spin.set_value (0);
+       hbox.pack_start (spin);
+       spin.set_value (_last_normalization_value);
+       hbox.pack_start (*manage (new Label (_("dbFS"))));
+       hbox.show_all ();
+       dialog.get_vbox()->pack_start (hbox);
+       dialog.add_button (Stock::CANCEL, RESPONSE_CANCEL);
+       dialog.add_button (_("Normalize"), RESPONSE_ACCEPT);
+
+       if (dialog.run () == RESPONSE_CANCEL) {
                return;
        }
 
@@ -4596,24 +4469,27 @@ Editor::normalize_region ()
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*r);
                if (!arv)
                        continue;
-               XMLNode &before = arv->region()->get_state();
-               arv->audio_region()->normalize_to (0.0f);
-               session->add_command (new MementoCommand<Region>(*(arv->region().get()), &before, &arv->region()->get_state()));
+                arv->region()->clear_history ();
+               arv->audio_region()->normalize_to (spin.get_value());
+               _session->add_command (new StatefulDiffCommand (arv->region()));
+                                       
        }
 
        commit_reversible_command ();
        track_canvas->get_window()->set_cursor (*current_canvas_cursor);
+
+       _last_normalization_value = spin.get_value ();
 }
 
 
 void
-Editor::denormalize_region ()
+Editor::reset_region_scale_amplitude ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -4621,15 +4497,15 @@ Editor::denormalize_region ()
                return;
        }
 
-       begin_reversible_command ("denormalize");
+       begin_reversible_command ("reset gain");
 
        for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*r);
                if (!arv)
                        continue;
-               XMLNode &before = arv->region()->get_state();
+                arv->region()->clear_history ();
                arv->audio_region()->set_scale_amplitude (1.0f);
-               session->add_command (new MementoCommand<Region>(*(arv->region().get()), &before, &arv->region()->get_state()));
+               _session->add_command (new StatefulDiffCommand (arv->region()));
        }
 
        commit_reversible_command ();
@@ -4638,11 +4514,11 @@ Editor::denormalize_region ()
 void
 Editor::adjust_region_scale_amplitude (bool up)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -4654,12 +4530,14 @@ Editor::adjust_region_scale_amplitude (bool up)
 
        for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*r);
-               if (!arv)
+               if (!arv) {
                        continue;
-               XMLNode &before = arv->region()->get_state();
-               
+                }
+
+                arv->region()->clear_history ();
+                
                double fraction = gain_to_slider_position (arv->audio_region()->scale_amplitude ());
-               
+
                if (up) {
                        fraction += 0.05;
                        fraction = min (fraction, 1.0);
@@ -4673,15 +4551,13 @@ Editor::adjust_region_scale_amplitude (bool up)
                }
 
                fraction = slider_position_to_gain (fraction);
-               fraction = coefficient_to_dB (fraction);
-               fraction = dB_to_coefficient (fraction);
 
                if (up && fraction >= 2.0) {
                        continue;
                }
-               
+
                arv->audio_region()->set_scale_amplitude (fraction);
-               session->add_command (new MementoCommand<Region>(*(arv->region().get()), &before, &arv->region()->get_state()));
+               _session->add_command (new StatefulDiffCommand (arv->region()));
        }
 
        commit_reversible_command ();
@@ -4691,18 +4567,18 @@ Editor::adjust_region_scale_amplitude (bool up)
 void
 Editor::reverse_region ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       Reverse rev (*session);
+       Reverse rev (*_session);
        apply_filter (rev, _("reverse regions"));
 }
 
 void
 Editor::strip_region_silence ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4714,40 +4590,97 @@ Editor::strip_region_silence ()
        }
 
        std::list<boost::shared_ptr<AudioRegion> > ar;
-       
+
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*> (*i);
                if (arv) {
                        ar.push_back (arv->audio_region ());
                }
        }
-       
-       StripSilenceDialog d (ar);
+
+       StripSilenceDialog d (_session, ar);
        int const r = d.run ();
 
        if (r == Gtk::RESPONSE_OK) {
-               StripSilence s (*session, d.threshold (), d.minimum_length (), d.fade_length ());
+               StripSilence s (*_session, d.threshold (), d.minimum_length (), d.fade_length ());
                apply_filter (s, _("strip silence"));
        }
 }
 
+Command*
+Editor::apply_midi_note_edit_op_to_region (MidiOperator& op, MidiRegionView& mrv)
+{
+       Evoral::Sequence<Evoral::MusicalTime>::Notes selected;
+       mrv.selection_as_notelist (selected);
+
+       vector<Evoral::Sequence<Evoral::MusicalTime>::Notes> v;
+       v.push_back (selected);
+
+       return op (mrv.midi_region()->model(), v);
+}
+
+void
+Editor::apply_midi_note_edit_op (MidiOperator& op)
+{
+       RegionSelection rs;
+       Command* cmd;
+
+       get_regions_for_action (rs);
+
+       if (rs.empty()) {
+               return;
+       }
+
+       begin_reversible_command (op.name ());
+
+       for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ) {
+               RegionSelection::iterator tmp = r;
+               ++tmp;
+
+               MidiRegionView* const mrv = dynamic_cast<MidiRegionView*> (*r);
+
+               if (mrv) {
+                       cmd = apply_midi_note_edit_op_to_region (op, *mrv);
+                       if (cmd) {
+                               (*cmd)();
+                               _session->add_command (cmd);
+                       }
+               }
+
+               r = tmp;
+       }
+
+       commit_reversible_command ();
+       rs.clear ();
+}
 
 void
 Editor::quantize_region ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       // FIXME: varying meter?
-       Quantize quant (*session, snap_length_beats(0));
-       apply_filter (quant, _("quantize regions"));
+       QuantizeDialog* qd = new QuantizeDialog (*this);
+
+       qd->present ();
+       const int r = qd->run ();
+       qd->hide ();
+
+       if (r == Gtk::RESPONSE_OK) {
+               Quantize quant (*_session, Plain,
+                               qd->snap_start(), qd->snap_end(),
+                               qd->start_grid_size(), qd->end_grid_size(),
+                               qd->strength(), qd->swing(), qd->threshold());
+
+               apply_midi_note_edit_op (quant);
+       }
 }
 
 void
 Editor::apply_filter (Filter& filter, string command)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -4764,26 +4697,19 @@ Editor::apply_filter (Filter& filter, string command)
                RegionSelection::iterator tmp = r;
                ++tmp;
 
-               MidiRegionView* const mrv = dynamic_cast<MidiRegionView*>(*r);
-               if (mrv) {
-                       if (mrv->midi_region()->apply(filter) == 0) {
-                               mrv->redisplay_model();
-                       }
-               }
-
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*r);
                if (arv) {
                        boost::shared_ptr<Playlist> playlist = arv->region()->playlist();
 
                        if (arv->audio_region()->apply (filter) == 0) {
 
-                               XMLNode &before = playlist->get_state();
-
+                               playlist->clear_history ();
+                                
                                if (filter.results.empty ()) {
 
                                        /* no regions returned; remove the old one */
                                        playlist->remove_region (arv->region ());
-                                       
+
                                } else {
 
                                        std::vector<boost::shared_ptr<Region> >::iterator res = filter.results.begin ();
@@ -4797,11 +4723,10 @@ Editor::apply_filter (Filter& filter, string command)
                                                playlist->add_region (*res, (*res)->position());
                                                ++res;
                                        }
-                                       
+
                                }
 
-                               XMLNode &after = playlist->get_state();
-                               session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
+                               _session->add_command(new StatefulDiffCommand (playlist));
                        } else {
                                goto out;
                        }
@@ -4855,7 +4780,7 @@ void
 Editor::brush (nframes64_t pos)
 {
        RegionSelection sel;
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -4873,15 +4798,13 @@ Editor::brush (nframes64_t pos)
 void
 Editor::reset_region_gain_envelopes ()
 {
-       RegionSelection rs; 
-
-       get_regions_for_action (rs);
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       if (!session || rs.empty()) {
+       if (!_session || rs.empty()) {
                return;
        }
 
-       session->begin_reversible_command (_("reset region gain"));
+       _session->begin_reversible_command (_("reset region gain"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*i);
@@ -4890,90 +4813,138 @@ Editor::reset_region_gain_envelopes ()
                        XMLNode& before (alist->get_state());
 
                        arv->audio_region()->set_default_envelope ();
-                       session->add_command (new MementoCommand<AutomationList>(*arv->audio_region()->envelope().get(), &before, &alist->get_state()));
+                       _session->add_command (new MementoCommand<AutomationList>(*arv->audio_region()->envelope().get(), &before, &alist->get_state()));
                }
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_gain_envelope_visibility ()
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region gain envelope visible"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*i);
                if (arv) {
+                        arv->region()->clear_history ();
                        arv->set_envelope_visible (!arv->envelope_visible());
+                       _session->add_command (new StatefulDiffCommand (arv->region()));
                }
        }
+
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_gain_envelope_active ()
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region gain envelope active"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*i);
                if (arv) {
+                       arv->region()->clear_history ();
                        arv->audio_region()->set_envelope_active (!arv->audio_region()->envelope_active());
+                       _session->add_command (new StatefulDiffCommand (arv->region()));
                }
        }
+
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_region_lock ()
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region lock"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
+               (*i)->region()->clear_history ();
                (*i)->region()->set_locked (!(*i)->region()->locked());
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
+
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::set_region_lock_style (Region::PositionLockStyle ps)
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region lock style"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
+                (*i)->region()->clear_history ();
                (*i)->region()->set_position_lock_style (ps);
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
+
+       _session->commit_reversible_command ();
 }
 
 
 void
 Editor::toggle_region_mute ()
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region mute"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
+               (*i)->region()->clear_history ();
                (*i)->region()->set_muted (!(*i)->region()->muted());
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
+
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_region_opaque ()
 {
-       RegionSelection rs
+       RegionSelection rs = get_equivalent_regions (selection->regions, ARDOUR::Properties::edit.property_id);
 
-       get_regions_for_action (rs);
+       if (!_session || rs.empty()) {
+               return;
+       }
+
+       _session->begin_reversible_command (_("region opacity"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
+               (*i)->region()->clear_history ();
                (*i)->region()->set_opaque (!(*i)->region()->opaque());
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
+
+       _session->commit_reversible_command ();
 }
 
 void
@@ -5001,26 +4972,22 @@ Editor::toggle_record_enable ()
 void
 Editor::set_fade_length (bool in)
 {
-       RegionSelection rs; 
-
-       get_regions_for_action (rs);
-
-       /* we need a region to measure the offset from the start */
+       RegionSelection rs;
 
-       RegionView* rv;
+       get_regions_for_action (rs, true);
 
-       if (!rs.empty()) {
-               rv = rs.front();
-       } else if (entered_regionview) {
-               rv = entered_regionview;
-       } else {
+       if (rs.empty()) {
                return;
        }
 
+       /* we need a region to measure the offset from the start */
+
+       RegionView* rv = rs.front ();
+
        nframes64_t pos = get_preferred_edit_position();
        nframes64_t len;
        char* cmd;
-       
+
        if (pos > rv->region()->last_frame() || pos < rv->region()->first_frame()) {
                /* edit point is outside the relevant region */
                return;
@@ -5067,9 +5034,9 @@ Editor::set_fade_length (bool in)
                        tmp->audio_region()->set_fade_out_length (len);
                        tmp->audio_region()->set_fade_out_active (true);
                }
-               
+
                XMLNode &after = alist->get_state();
-               session->add_command(new MementoCommand<AutomationList>(*alist, &before, &after));
+               _session->add_command(new MementoCommand<AutomationList>(*alist, &before, &after));
        }
 
        commit_reversible_command ();
@@ -5078,7 +5045,7 @@ Editor::set_fade_length (bool in)
 void
 Editor::toggle_fade_active (bool in)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5094,7 +5061,7 @@ Editor::toggle_fade_active (bool in)
 
        for (RegionSelection::iterator x = rs.begin(); x != rs.end(); ++x) {
                AudioRegionView* tmp = dynamic_cast<AudioRegionView*> (*x);
-               
+
                if (!tmp) {
                        return;
                }
@@ -5102,7 +5069,7 @@ Editor::toggle_fade_active (bool in)
                boost::shared_ptr<AudioRegion> region (tmp->audio_region());
 
                /* make the behaviour consistent across all regions */
-               
+
                if (!have_switch) {
                        if (in) {
                                yn = region->fade_in_active();
@@ -5112,14 +5079,15 @@ Editor::toggle_fade_active (bool in)
                        have_switch = true;
                }
 
-               XMLNode &before = region->get_state();
+               region->clear_history ();
+
                if (in) {
                        region->set_fade_in_active (!yn);
                } else {
                        region->set_fade_out_active (!yn);
                }
-               XMLNode &after = region->get_state();
-               session->add_command(new MementoCommand<AudioRegion>(*region.get(), &before, &after));
+               
+               _session->add_command(new StatefulDiffCommand (region));
        }
 
        commit_reversible_command ();
@@ -5128,7 +5096,7 @@ Editor::toggle_fade_active (bool in)
 void
 Editor::set_fade_in_shape (AudioRegion::FadeShape shape)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5149,19 +5117,19 @@ Editor::set_fade_in_shape (AudioRegion::FadeShape shape)
                XMLNode &before = alist->get_state();
 
                tmp->audio_region()->set_fade_in_shape (shape);
-               
+
                XMLNode &after = alist->get_state();
-               session->add_command(new MementoCommand<AutomationList>(*alist.get(), &before, &after));
+               _session->add_command(new MementoCommand<AutomationList>(*alist.get(), &before, &after));
        }
 
        commit_reversible_command ();
-               
+
 }
 
 void
 Editor::set_fade_out_shape (AudioRegion::FadeShape shape)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5182,9 +5150,9 @@ Editor::set_fade_out_shape (AudioRegion::FadeShape shape)
                XMLNode &before = alist->get_state();
 
                tmp->audio_region()->set_fade_out_shape (shape);
-               
+
                XMLNode &after = alist->get_state();
-               session->add_command(new MementoCommand<AutomationList>(*alist.get(), &before, &after));
+               _session->add_command(new MementoCommand<AutomationList>(*alist.get(), &before, &after));
        }
 
        commit_reversible_command ();
@@ -5193,7 +5161,7 @@ Editor::set_fade_out_shape (AudioRegion::FadeShape shape)
 void
 Editor::set_fade_in_active (bool yn)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5212,13 +5180,10 @@ Editor::set_fade_in_active (bool yn)
 
 
                boost::shared_ptr<AudioRegion> ar (tmp->audio_region());
-
-               XMLNode &before = ar->get_state();
-
-               ar->set_fade_in_active (yn);
                
-               XMLNode &after = ar->get_state();
-               session->add_command(new MementoCommand<AudioRegion>(*ar, &before, &after));
+                ar->clear_history ();
+               ar->set_fade_in_active (yn);
+               _session->add_command (new StatefulDiffCommand (ar));
        }
 
        commit_reversible_command ();
@@ -5227,7 +5192,7 @@ Editor::set_fade_in_active (bool yn)
 void
 Editor::set_fade_out_active (bool yn)
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5246,12 +5211,9 @@ Editor::set_fade_out_active (bool yn)
 
                boost::shared_ptr<AudioRegion> ar (tmp->audio_region());
 
-               XMLNode &before = ar->get_state();
-
+                ar->clear_history ();
                ar->set_fade_out_active (yn);
-               
-               XMLNode &after = ar->get_state();
-               session->add_command(new MementoCommand<AudioRegion>(*ar, &before, &after));
+               _session->add_command(new StatefulDiffCommand (ar));
        }
 
        commit_reversible_command ();
@@ -5266,7 +5228,7 @@ Editor::toggle_selected_region_fades (int dir)
        bool yn;
 
        get_regions_for_action (rs);
-       
+
        if (rs.empty()) {
                return;
        }
@@ -5307,7 +5269,7 @@ Editor::toggle_selected_region_fades (int dir)
 void
 Editor::update_region_fade_visibility ()
 {
-       bool _fade_visibility = session->config.get_show_region_fades ();
+       bool _fade_visibility = _session->config.get_show_region_fades ();
 
        for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
                AudioTimeAxisView* v = dynamic_cast<AudioTimeAxisView*>(*i);
@@ -5325,8 +5287,8 @@ Editor::update_region_fade_visibility ()
 void
 Editor::update_xfade_visibility ()
 {
-       _xfade_visibility = session->config.get_xfades_visible ();
-       
+       _xfade_visibility = _session->config.get_xfades_visible ();
+
        for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
                AudioTimeAxisView* v = dynamic_cast<AudioTimeAxisView*>(*i);
                if (v) {
@@ -5348,11 +5310,11 @@ Editor::set_edit_point ()
        if (!mouse_frame (where, ignored)) {
                return;
        }
-       
+
        snap_to (where);
 
        if (selection->markers.empty()) {
-               
+
                mouse_add_new_marker (where);
 
        } else {
@@ -5370,7 +5332,7 @@ void
 Editor::set_playhead_cursor ()
 {
        if (entered_marker) {
-               session->request_locate (entered_marker->position(), session->transport_rolling());
+               _session->request_locate (entered_marker->position(), _session->transport_rolling());
        } else {
                nframes64_t where;
                bool ignored;
@@ -5378,11 +5340,11 @@ Editor::set_playhead_cursor ()
                if (!mouse_frame (where, ignored)) {
                        return;
                }
-                       
+
                snap_to (where);
-               
-               if (session) {
-                       session->request_locate (where, session->transport_rolling());
+
+               if (_session) {
+                       _session->request_locate (where, _session->transport_rolling());
                }
        }
 }
@@ -5390,9 +5352,9 @@ Editor::set_playhead_cursor ()
 void
 Editor::split ()
 {
-       RegionSelection rs; 
-       
-       get_regions_for_action (rs);
+       RegionSelection rs;
+
+       get_regions_for_action (rs, true);
 
        nframes64_t where = get_preferred_edit_position();
 
@@ -5524,31 +5486,31 @@ Editor::ensure_track_visible(TimeAxisView *track)
 void
 Editor::set_loop_from_selection (bool play)
 {
-       if (session == 0 || selection->time.empty()) {
+       if (_session == 0 || selection->time.empty()) {
                return;
        }
 
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
-       
+
        set_loop_range (start, end,  _("set loop range from selection"));
 
        if (play) {
-               session->request_play_loop (true);
-               session->request_locate (start, true);
+               _session->request_play_loop (true);
+               _session->request_locate (start, true);
        }
 }
 
 void
 Editor::set_loop_from_edit_range (bool play)
 {
-       if (session == 0) {
+       if (_session == 0) {
                return;
        }
 
        nframes64_t start;
        nframes64_t end;
-       
+
        if (!get_edit_op_range (start, end)) {
                return;
        }
@@ -5556,8 +5518,8 @@ Editor::set_loop_from_edit_range (bool play)
        set_loop_range (start, end,  _("set loop range from edit range"));
 
        if (play) {
-               session->request_play_loop (true);
-               session->request_locate (start, true);
+               _session->request_play_loop (true);
+               _session->request_locate (start, true);
        }
 }
 
@@ -5567,7 +5529,7 @@ Editor::set_loop_from_region (bool play)
        nframes64_t start = max_frames;
        nframes64_t end = 0;
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5587,34 +5549,34 @@ Editor::set_loop_from_region (bool play)
        set_loop_range (start, end, _("set loop range from region"));
 
        if (play) {
-               session->request_play_loop (true);
-               session->request_locate (start, true);
+               _session->request_play_loop (true);
+               _session->request_locate (start, true);
        }
 }
 
 void
 Editor::set_punch_from_selection ()
 {
-       if (session == 0 || selection->time.empty()) {
+       if (_session == 0 || selection->time.empty()) {
                return;
        }
 
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
-       
+
        set_punch_range (start, end,  _("set punch range from selection"));
 }
 
 void
 Editor::set_punch_from_edit_range ()
 {
-       if (session == 0) {
+       if (_session == 0) {
                return;
        }
 
        nframes64_t start;
        nframes64_t end;
-       
+
        if (!get_edit_op_range (start, end)) {
                return;
        }
@@ -5628,7 +5590,7 @@ Editor::set_punch_from_region ()
        nframes64_t start = max_frames;
        nframes64_t end = 0;
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5651,25 +5613,25 @@ Editor::set_punch_from_region ()
 void
 Editor::pitch_shift_regions ()
 {
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
-       
+
        if (rs.empty()) {
                return;
        }
 
        pitch_shift (rs, 1.2);
 }
-       
+
 void
 Editor::use_region_as_bar ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5695,8 +5657,8 @@ void
 Editor::define_one_bar (nframes64_t start, nframes64_t end)
 {
        nframes64_t length = end - start;
-       
-       const Meter& m (session->tempo_map().meter_at (start));
+
+       const Meter& m (_session->tempo_map().meter_at (start));
 
        /* length = 1 bar */
 
@@ -5705,24 +5667,24 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
        */
 
        double frames_per_beat = length / m.beats_per_bar();
-       
+
        /* beats per minute = */
 
-       double beats_per_minute = (session->frame_rate() * 60.0) / frames_per_beat;
+       double beats_per_minute = (_session->frame_rate() * 60.0) / frames_per_beat;
 
        /* now decide whether to:
 
-           (a) set global tempo 
+           (a) set global tempo
            (b) add a new tempo marker
 
        */
 
-       const TempoSection& t (session->tempo_map().tempo_section_at (start));
+       const TempoSection& t (_session->tempo_map().tempo_section_at (start));
 
        bool do_global = false;
 
-       if ((session->tempo_map().n_tempos() == 1) && (session->tempo_map().n_meters() == 1)) {
-               
+       if ((_session->tempo_map().n_tempos() == 1) && (_session->tempo_map().n_meters() == 1)) {
+
                /* only 1 tempo & 1 meter: ask if the user wants to set the tempo
                   at the start, or create a new marker
                */
@@ -5731,8 +5693,13 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
                options.push_back (_("Cancel"));
                options.push_back (_("Add new marker"));
                options.push_back (_("Set global tempo"));
-               Choice c (_("Do you want to set the global tempo or add new tempo marker?"),
-                         options);
+
+               Choice c (
+                       _("Define one bar"),
+                       _("Do you want to set the global tempo or add a new tempo marker?"),
+                       options
+                       );
+               
                c.set_default_response (2);
 
                switch (c.run()) {
@@ -5751,24 +5718,24 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
 
                /* more than 1 tempo and/or meter section already, go ahead do the "usual":
                   if the marker is at the region starter, change it, otherwise add
-                  a new tempo marker 
+                  a new tempo marker
                */
        }
 
        begin_reversible_command (_("set tempo from region"));
-       XMLNode& before (session->tempo_map().get_state());
+       XMLNode& before (_session->tempo_map().get_state());
 
        if (do_global) {
-               session->tempo_map().change_initial_tempo (beats_per_minute, t.note_type());
+               _session->tempo_map().change_initial_tempo (beats_per_minute, t.note_type());
        } else if (t.frame() == start) {
-               session->tempo_map().change_existing_tempo_at (start, beats_per_minute, t.note_type());
+               _session->tempo_map().change_existing_tempo_at (start, beats_per_minute, t.note_type());
        } else {
-               session->tempo_map().add_tempo (Tempo (beats_per_minute, t.note_type()), start);
+               _session->tempo_map().add_tempo (Tempo (beats_per_minute, t.note_type()), start);
        }
 
-       XMLNode& after (session->tempo_map().get_state());
+       XMLNode& after (_session->tempo_map().get_state());
 
-       session->add_command (new MementoCommand<TempoMap>(session->tempo_map(), &before, &after));
+       _session->add_command (new MementoCommand<TempoMap>(_session->tempo_map(), &before, &after));
        commit_reversible_command ();
 }
 
@@ -5777,11 +5744,11 @@ Editor::split_region_at_transients ()
 {
        AnalysisFeatureList positions;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       RegionSelection rs; 
+       RegionSelection rs;
 
        get_regions_for_action (rs);
 
@@ -5789,7 +5756,7 @@ Editor::split_region_at_transients ()
                return;
        }
 
-       session->begin_reversible_command (_("split regions"));
+       _session->begin_reversible_command (_("split regions"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ) {
 
@@ -5799,16 +5766,16 @@ Editor::split_region_at_transients ()
                ++tmp;
 
                boost::shared_ptr<AudioRegion> ar = boost::dynamic_pointer_cast<AudioRegion> ((*i)->region());
-               
+
                if (ar && (ar->get_transients (positions) == 0)) {
                        split_region_at_points ((*i)->region(), positions, true);
                        positions.clear ();
                }
-               
+
                i = tmp;
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 
 }
 
@@ -5818,11 +5785,11 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
        bool use_rhythmic_rodent = false;
 
        boost::shared_ptr<Playlist> pl = r->playlist();
-       
+
        if (!pl) {
                return;
        }
-       
+
        if (positions.empty()) {
                return;
        }
@@ -5857,44 +5824,44 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
                        return;
                }
        }
-       
+
        if (use_rhythmic_rodent) {
                show_rhythm_ferret ();
                return;
        }
 
-       AnalysisFeatureList::const_iterator x;  
-       
+       AnalysisFeatureList::const_iterator x;
+
        nframes64_t pos = r->position();
 
-       XMLNode& before (pl->get_state());
-       
+        pl->clear_history ();
+
        x = positions.begin();
-       
+
        while (x != positions.end()) {
                if ((*x) > pos) {
                        break;
                }
                ++x;
        }
-       
+
        if (x == positions.end()) {
                return;
        }
-       
+
        pl->freeze ();
        pl->remove_region (r);
-       
+
        while (x != positions.end()) {
-               
-               /* file start = original start + how far we from the initial position ? 
+
+               /* file start = original start + how far we from the initial position ?
                 */
-               
+
                nframes64_t file_start = r->start() + (pos - r->position());
 
                /* length = next position - current position
                 */
-               
+
                nframes64_t len = (*x) - pos;
 
                /* XXX we do we really want to allow even single-sample regions?
@@ -5904,16 +5871,23 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
                if (len <= 0) {
                        break;
                }
-               
+
                string new_name;
-               
-               if (session->region_name (new_name, r->name())) {
+
+               if (RegionFactory::region_name (new_name, r->name())) {
                        break;
                }
-               
+
                /* do NOT announce new regions 1 by one, just wait till they are all done */
 
-               boost::shared_ptr<Region> nr = RegionFactory::create (r->sources(), file_start, len, new_name, 0, Region::DefaultFlags, false);
+               PropertyList plist; 
+               
+               plist.add (ARDOUR::Properties::start, file_start);
+               plist.add (ARDOUR::Properties::length, len);
+               plist.add (ARDOUR::Properties::name, new_name);
+               plist.add (ARDOUR::Properties::layer, 0);
+
+               boost::shared_ptr<Region> nr = RegionFactory::create (r->sources(), plist, false);
                pl->add_region (nr, pos);
 
                pos += len;
@@ -5922,22 +5896,27 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
                if (*x > r->last_frame()) {
 
                        /* add final fragment */
-                       
+
                        file_start = r->start() + (pos - r->position());
                        len = r->last_frame() - pos;
 
-                       nr = RegionFactory::create (r->sources(), file_start, len, new_name, 0, Region::DefaultFlags);
+                       PropertyList plist2; 
+                       
+                       plist2.add (ARDOUR::Properties::start, file_start);
+                       plist2.add (ARDOUR::Properties::length, len);
+                       plist2.add (ARDOUR::Properties::name, new_name);
+                       plist2.add (ARDOUR::Properties::layer, 0);
+
+                       nr = RegionFactory::create (r->sources(), plist2); 
                        pl->add_region (nr, pos);
 
                        break;
                }
-       } 
+       }
 
        pl->thaw ();
 
-       XMLNode& after (pl->get_state());
-       
-       session->add_command (new MementoCommand<Playlist>(*pl, &before, &after));
+       _session->add_command (new StatefulDiffCommand (pl));
 }
 
 void
@@ -5945,11 +5924,11 @@ Editor::tab_to_transient (bool forward)
 {
        AnalysisFeatureList positions;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       nframes64_t pos = session->audible_frame ();
+       nframes64_t pos = _session->audible_frame ();
 
        if (!selection->tracks.empty()) {
 
@@ -5958,12 +5937,12 @@ Editor::tab_to_transient (bool forward)
                        RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (*t);
 
                        if (rtv) {
-                               boost::shared_ptr<Diskstream> ds = rtv->get_diskstream();
-                               if (ds) {
-                                       boost::shared_ptr<Playlist> pl = rtv->get_diskstream()->playlist ();
+                               boost::shared_ptr<Track> tr = rtv->track();
+                               if (tr) {
+                                       boost::shared_ptr<Playlist> pl = tr->playlist ();
                                        if (pl) {
                                                nframes64_t result = pl->find_next_transient (pos, forward ? 1 : -1);
-                                               
+
                                                if (result >= 0) {
                                                        positions.push_back (result);
                                                }
@@ -5973,21 +5952,21 @@ Editor::tab_to_transient (bool forward)
                }
 
        } else {
-               
-               RegionSelection rs; 
+
+               RegionSelection rs;
 
                get_regions_for_action (rs);
-       
+
                if (rs.empty()) {
                        return;
                }
-               
+
                for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
                        (*r)->region()->get_transients (positions);
                }
        }
 
-       TransientDetector::cleanup_transients (positions, session->frame_rate(), 3.0);
+       TransientDetector::cleanup_transients (positions, _session->frame_rate(), 3.0);
 
        if (forward) {
                AnalysisFeatureList::iterator x;
@@ -5999,7 +5978,7 @@ Editor::tab_to_transient (bool forward)
                }
 
                if (x != positions.end ()) {
-                       session->request_locate (*x);
+                       _session->request_locate (*x);
                }
 
        } else {
@@ -6012,19 +5991,19 @@ Editor::tab_to_transient (bool forward)
                }
 
                if (x != positions.rend ()) {
-                       session->request_locate (*x);
+                       _session->request_locate (*x);
                }
        }
 }
 void
 Editor::playhead_forward_to_grid ()
 {
-       if (!session) return;
+       if (!_session) return;
        nframes64_t pos = playhead_cursor->current_frame;
        if (pos < max_frames - 1) {
                pos += 2;
                snap_to_internal (pos, 1, false);
-               session->request_locate (pos);
+               _session->request_locate (pos);
        }
 }
 
@@ -6032,12 +6011,12 @@ Editor::playhead_forward_to_grid ()
 void
 Editor::playhead_backward_to_grid ()
 {
-       if (!session) return;
+       if (!_session) return;
        nframes64_t pos = playhead_cursor->current_frame;
        if (pos > 2) {
                pos -= 2;
                snap_to_internal (pos, -1, false);
-               session->request_locate (pos);
+               _session->request_locate (pos);
        }
 }
 
@@ -6046,10 +6025,6 @@ Editor::set_track_height (uint32_t h)
 {
        TrackSelection& ts (selection->tracks);
 
-       if (ts.empty()) {
-               return;
-       }
-
        for (TrackSelection::iterator x = ts.begin(); x != ts.end(); ++x) {
                (*x)->set_height (h);
        }
@@ -6107,7 +6082,7 @@ Editor::remove_tracks ()
                }
                routes.push_back (rtv->_route);
        }
-       
+
        if (ntracks + nbusses == 0) {
                return;
        }
@@ -6148,14 +6123,21 @@ Editor::remove_tracks ()
                choices.push_back (_("Yes, remove it."));
        }
 
-       Choice prompter (prompt, choices);
+       string title;
+       if (ntracks) {
+               title = string_compose (_("Remove %1"), trackstr);
+       } else {
+               title = string_compose (_("Remove %1"), busstr);
+       }
+
+       Choice prompter (title, prompt, choices);
 
        if (prompter.run () != 1) {
                return;
        }
 
        for (vector<boost::shared_ptr<Route> >::iterator x = routes.begin(); x != routes.end(); ++x) {
-               session->remove_route (*x);
+               _session->remove_route (*x);
        }
 }
 
@@ -6169,7 +6151,7 @@ Editor::do_insert_time ()
        ArdourDialog d (*this, _("Insert Time"));
 
        nframes64_t const pos = get_preferred_edit_position ();
-       
+
        d.get_vbox()->set_border_width (12);
        d.get_vbox()->set_spacing (4);
 
@@ -6179,10 +6161,10 @@ Editor::do_insert_time ()
        Label time_label (_("Time to insert:"));
        time_label.set_alignment (1, 0.5);
        table.attach (time_label, 0, 1, 0, 1, FILL | EXPAND);
-       AudioClock clock ("insertTimeClock", true, X_("InsertTimeClock"), true, true, true);
+       AudioClock clock ("insertTimeClock", true, X_("InsertTimeClock"), true, false, true, true);
        clock.set (0);
-       clock.set_session (session);
-       clock.set_bbt_reference (pos);  
+       clock.set_session (_session);
+       clock.set_bbt_reference (pos);
        table.attach (clock, 1, 2, 0, 1);
 
        Label intersected_label (_("Intersected regions should:"));
@@ -6203,7 +6185,7 @@ Editor::do_insert_time ()
        d.get_vbox()->pack_start (move_markers);
        CheckButton move_tempos (_("Move tempo and meter changes"));
        d.get_vbox()->pack_start (move_tempos);
-       
+
        d.add_button (Gtk::Stock::CANCEL, Gtk::RESPONSE_CANCEL);
        d.add_button (_("Insert time"), Gtk::RESPONSE_OK);
        d.show_all ();
@@ -6238,7 +6220,7 @@ Editor::do_insert_time ()
 }
 
 void
-Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt, 
+Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
                     bool ignore_music_glue, bool markers_too, bool tempo_too)
 {
        bool commit = false;
@@ -6252,23 +6234,32 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
        for (TrackSelection::iterator x = selection->tracks.begin(); x != selection->tracks.end(); ++x) {
                /* regions */
                boost::shared_ptr<Playlist> pl = (*x)->playlist();
-               
+
                if (pl) {
 
-                       XMLNode &before = pl->get_state();
-                       
+                       pl->clear_history ();
+                        pl->clear_owned_history ();
+
                        if (opt == SplitIntersected) {
                                pl->split (pos);
                        }
-                       
+
                        pl->shift (pos, frames, (opt == MoveIntersected), ignore_music_glue);
-                       
-                       XMLNode &after = pl->get_state();
-                       
-                       session->add_command (new MementoCommand<Playlist> (*pl, &before, &after));
+
+                        vector<StatefulDiffCommand*> cmds;
+                        
+                        pl->rdiff (cmds);
+                        
+                        cerr << "Shift generated " << cmds.size() << " sdc's\n";
+
+                        for (vector<StatefulDiffCommand*>::iterator c = cmds.begin(); c != cmds.end(); ++c) {
+                                _session->add_command (*c);
+                        }
+                        
+                       _session->add_command (new StatefulDiffCommand (pl));
                        commit = true;
                }
-                       
+
                /* automation */
                RouteTimeAxisView* rtav = dynamic_cast<RouteTimeAxisView*> (*x);
                if (rtav) {
@@ -6280,11 +6271,11 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
        /* markers */
        if (markers_too) {
                bool moved = false;
-               XMLNode& before (session->locations()->get_state());
-               Locations::LocationList copy (session->locations()->list());
+               XMLNode& before (_session->locations()->get_state());
+               Locations::LocationList copy (_session->locations()->list());
 
                for (Locations::LocationList::iterator i = copy.begin(); i != copy.end(); ++i) {
-                       
+
                        Locations::LocationList::const_iterator tmp;
 
                        if ((*i)->start() >= pos) {
@@ -6297,13 +6288,13 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
                }
 
                if (moved) {
-                       XMLNode& after (session->locations()->get_state());
-                       session->add_command (new MementoCommand<Locations>(*session->locations(), &before, &after));
+                       XMLNode& after (_session->locations()->get_state());
+                       _session->add_command (new MementoCommand<Locations>(*_session->locations(), &before, &after));
                }
        }
 
        if (tempo_too) {
-               session->tempo_map().insert_time (pos, frames);
+               _session->tempo_map().insert_time (pos, frames);
        }
 
        if (commit) {
@@ -6312,15 +6303,21 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
 }
 
 void
-Editor::fit_tracks ()
+Editor::fit_selected_tracks ()
 {
-       if (selection->tracks.empty()) {
+       fit_tracks (selection->tracks);
+}
+
+void
+Editor::fit_tracks (TrackViewList & tracks)
+{
+       if (tracks.empty()) {
                return;
        }
 
        uint32_t child_heights = 0;
 
-       for (TrackSelection::iterator t = selection->tracks.begin(); t != selection->tracks.end(); ++t) {
+       for (TrackSelection::iterator t = tracks.begin(); t != tracks.end(); ++t) {
 
                if (!(*t)->marked_for_display()) {
                        continue;
@@ -6329,32 +6326,32 @@ Editor::fit_tracks ()
                child_heights += (*t)->effective_height() - (*t)->current_height();
        }
 
-       uint32_t h = (uint32_t) floor ((canvas_height - child_heights - canvas_timebars_vsize)/selection->tracks.size());
+       uint32_t h = (uint32_t) floor ((_canvas_height - child_heights - canvas_timebars_vsize) / tracks.size());
        double first_y_pos = DBL_MAX;
 
        if (h < TimeAxisView::hSmall) {
-               MessageDialog msg (*this, _("There are too many selected tracks to fit in the current window"));
+               MessageDialog msg (*this, _("There are too many tracks to fit in the current window"));
                /* too small to be displayed */
                return;
        }
 
        undo_visual_stack.push_back (current_visual_state());
-       
+
        /* operate on all tracks, hide unselected ones that are in the middle of selected ones */
-       
+
        bool prev_was_selected = false;
-       bool is_selected = selection->selected (track_views.front());
+       bool is_selected = tracks.contains (track_views.front());
        bool next_is_selected;
 
        for (TrackViewList::iterator t = track_views.begin(); t != track_views.end(); ++t) {
 
                TrackViewList::iterator next;
-               
+
                next = t;
                ++next;
-               
+
                if (next != track_views.end()) {
-                       next_is_selected = selection->selected (*next);
+                       next_is_selected = tracks.contains (*next);
                } else {
                        next_is_selected = false;
                }
@@ -6372,10 +6369,10 @@ Editor::fit_tracks ()
                is_selected = next_is_selected;
        }
 
-       /* 
-          set the controls_layout height now, because waiting for its size 
-          request signal handler will cause the vertical adjustment setting to fail 
-       */ 
+       /*
+          set the controls_layout height now, because waiting for its size
+          request signal handler will cause the vertical adjustment setting to fail
+       */
 
        controls_layout.property_height () = full_canvas_height - canvas_timebars_vsize;
        vertical_adjustment.set_value (first_y_pos);
@@ -6413,10 +6410,8 @@ Editor::goto_visual_state (uint32_t n)
 void
 Editor::start_visual_state_op (uint32_t n)
 {
-       cerr << "Start visual op\n";
        if (visual_state_op_connection.empty()) {
-               visual_state_op_connection = Glib::signal_timeout().connect (bind (mem_fun (*this, &Editor::end_visual_state_op), n), 1000);
-               cerr << "\tqueued new timeout\n";
+               visual_state_op_connection = Glib::signal_timeout().connect (sigc::bind (sigc::mem_fun (*this, &Editor::end_visual_state_op), n), 1000);
        }
 }
 
@@ -6424,11 +6419,13 @@ void
 Editor::cancel_visual_state_op (uint32_t n)
 {
        if (!visual_state_op_connection.empty()) {
-               cerr << "cancel visual op, time to goto\n";
                visual_state_op_connection.disconnect();
                goto_visual_state (n);
-       } else {
-               cerr << "cancel visual op, do nothing\n";
+       }  else {
+               //we land here if called from the menu OR if end_visual_state_op has been called
+               //so check if we are already in visual state n
+               // XXX not yet checking it at all, but redoing does not hurt
+               goto_visual_state (n);
        }
 }
 
@@ -6437,7 +6434,7 @@ Editor::end_visual_state_op (uint32_t n)
 {
        visual_state_op_connection.disconnect();
        save_visual_state (n);
-       
+
        PopUp* pup = new PopUp (WIN_POS_MOUSE, 1000, true);
        char buf[32];
        snprintf (buf, sizeof (buf), _("Saved view %u"), n+1);