Allow markers to be glued to bar/beat time. Fixes #1815.
[ardour.git] / gtk2_ardour / editor_ops.cc
index 833ac580a2b262809ab1c5d882436d91b7a22a79..2eb3987b8915fe75f8c6765e4ad58844dc3c9173 100644 (file)
@@ -32,6 +32,7 @@
 #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 "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;
@@ -97,16 +98,16 @@ using Gtkmm2ext::Keyboard;
 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);
        }
 }
 
@@ -155,7 +156,12 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
 
                boost::shared_ptr<Playlist> pl = (*a)->region()->playlist();
 
-               if (! pl->frozen()) {
+                if (!pl) {
+                        a = tmp;
+                        continue;
+                }
+
+               if (!pl->frozen()) {
                        /* we haven't seen this playlist before */
 
                        /* remember used playlists so we can thaw them later */
@@ -163,16 +169,10 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
                        pl->freeze();
                }
 
-               AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*a);
-               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;
@@ -185,7 +185,6 @@ Editor::split_regions_at (nframes64_t where, RegionSelection& regions)
        }
 
        commit_reversible_command ();
-       _new_regionviews_show_envelope = false;
 }
 
 boost::shared_ptr<Region>
@@ -248,14 +247,8 @@ 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 ();
 }
 
@@ -278,12 +271,8 @@ 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 ();
 }
 
@@ -319,7 +308,7 @@ Editor::nudge_forward (bool next, bool force_playhead)
 
        get_regions_for_action (rs);
 
-       if (!session) return;
+       if (!_session) return;
 
        if (!force_playhead && !rs.empty()) {
 
@@ -334,10 +323,9 @@ Editor::nudge_forward (bool next, bool force_playhead)
                                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 ();
@@ -379,7 +367,7 @@ 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));
                        }
                }
 
@@ -387,7 +375,7 @@ Editor::nudge_forward (bool next, bool force_playhead)
 
        } 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);
        }
 }
 
@@ -400,7 +388,7 @@ Editor::nudge_backward (bool next, bool force_playhead)
 
        get_regions_for_action (rs);
 
-       if (!session) return;
+       if (!_session) return;
 
        if (!force_playhead && !rs.empty()) {
 
@@ -414,16 +402,15 @@ Editor::nudge_backward (bool next, bool force_playhead)
                        if (next) {
                                distance = next_distance;
                        }
-
-                        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 ();
@@ -467,7 +454,7 @@ Editor::nudge_backward (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));
                        }
                }
 
@@ -478,9 +465,9 @@ Editor::nudge_backward (bool next, bool force_playhead)
                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();
                }
        }
 }
@@ -493,21 +480,20 @@ Editor::nudge_forward_capture_offset ()
 
        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 ();
@@ -523,26 +509,25 @@ Editor::nudge_backward_capture_offset ()
 
        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 ();
@@ -554,20 +539,20 @@ 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
 Editor::build_region_boundary_cache ()
 {
-       nframes64_t pos = 0;
+       framepos_t pos = 0;
        vector<RegionPoint> interesting_points;
        boost::shared_ptr<Region> r;
        TrackViewList tracks;
@@ -575,7 +560,7 @@ Editor::build_region_boundary_cache ()
 
        region_boundary_cache.clear ();
 
-       if (session == 0) {
+       if (_session == 0) {
                return;
        }
 
@@ -608,10 +593,10 @@ 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;
+               framepos_t rpos;
+               framepos_t lpos = max_frames;
 
                for (vector<RegionPoint>::iterator p = interesting_points.begin(); p != interesting_points.end(); ++p) {
 
@@ -645,8 +630,8 @@ Editor::build_region_boundary_cache ()
                        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();
                                }
                        }
 
@@ -660,7 +645,7 @@ Editor::build_region_boundary_cache ()
                           to sort later.
                        */
 
-                       vector<nframes64_t>::iterator ri;
+                       vector<framepos_t>::iterator ri;
 
                        for (ri = region_boundary_cache.begin(); ri != region_boundary_cache.end(); ++ri) {
                                if (*ri == rpos) {
@@ -679,29 +664,35 @@ Editor::build_region_boundary_cache ()
        /* finally sort to be sure that the order is correct */
 
        sort (region_boundary_cache.begin(), region_boundary_cache.end());
+
+        cerr << "RBC contains " << region_boundary_cache.size() << endl;
+
+        for (vector<framepos_t>::iterator x = region_boundary_cache.begin(); x != region_boundary_cache.end(); ++x) {
+                cerr << "Region boundary @ " << *x << endl;
+        }
 }
 
 boost::shared_ptr<Region>
-Editor::find_next_region (nframes64_t frame, RegionPoint point, int32_t dir, TrackViewList& tracks, TimeAxisView **ontrack)
+Editor::find_next_region (framepos_t frame, RegionPoint point, int32_t dir, TrackViewList& tracks, TimeAxisView **ontrack)
 {
        TrackViewList::iterator i;
        nframes64_t closest = max_frames;
        boost::shared_ptr<Region> ret;
-       nframes64_t rpos = 0;
+       framepos_t rpos = 0;
 
        float track_speed;
-       nframes64_t track_frame;
+       framepos_t track_frame;
        RouteTimeAxisView *rtav;
 
        for (i = tracks.begin(); i != tracks.end(); ++i) {
 
-               nframes64_t distance;
+               framecnt_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);
@@ -725,7 +716,7 @@ 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) {
@@ -745,17 +736,16 @@ Editor::find_next_region (nframes64_t frame, RegionPoint point, int32_t dir, Tra
        return ret;
 }
 
-nframes64_t
-Editor::find_next_region_boundary (nframes64_t pos, int32_t dir, const TrackViewList& tracks)
+framepos_t
+Editor::find_next_region_boundary (framepos_t pos, int32_t dir, const TrackViewList& tracks)
 {
-       nframes64_t distance = max_frames;
-       nframes64_t current_nearest = -1;
-
+       framecnt_t distance = max_frames;
+       framepos_t current_nearest = -1;
 
        for (TrackViewList::const_iterator i = tracks.begin(); i != tracks.end(); ++i) {
-               nframes64_t contender;
-               nframes64_t d;
-
+               framepos_t contender;
+               framecnt_t d;
+                
                RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (*i);
 
                if (!rtv) {
@@ -777,10 +767,10 @@ Editor::find_next_region_boundary (nframes64_t pos, int32_t dir, const TrackView
        return current_nearest;
 }
 
-nframes64_t
-Editor::get_region_boundary (nframes64_t pos, int32_t dir, bool with_selection, bool only_onscreen)
+framepos_t
+Editor::get_region_boundary (framepos_t pos, int32_t dir, bool with_selection, bool only_onscreen)
 {
-       nframes64_t target;
+       framepos_t target;
        TrackViewList tvl;
 
        if (with_selection && Config->get_region_boundaries_from_selected_tracks()) {
@@ -818,7 +808,7 @@ 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;
        }
 
@@ -831,8 +821,7 @@ Editor::cursor_to_region_boundary (bool with_selection, int32_t dir)
                return;
        }
 
-
-       session->request_locate (target);
+       _session->request_locate (target);
 }
 
 void
@@ -853,7 +842,7 @@ 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;
        }
 
@@ -902,15 +891,15 @@ Editor::cursor_to_region_point (EditorCursor* cursor, RegionPoint point, int32_t
        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);
        }
@@ -954,7 +943,7 @@ Editor::cursor_to_selection_start (EditorCursor *cursor)
        }
 
        if (cursor == playhead_cursor) {
-               session->request_locate (pos);
+               _session->request_locate (pos);
        } else {
                cursor->set_position (pos);
        }
@@ -986,7 +975,7 @@ Editor::cursor_to_selection_end (EditorCursor *cursor)
        }
 
        if (cursor == playhead_cursor) {
-               session->request_locate (pos);
+               _session->request_locate (pos);
        } else {
                cursor->set_position (pos);
        }
@@ -999,7 +988,7 @@ Editor::selected_marker_to_region_boundary (bool with_selection, int32_t dir)
        Location* loc;
        bool ignored;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -1052,7 +1041,7 @@ 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;
        }
 
@@ -1099,8 +1088,8 @@ Editor::selected_marker_to_region_point (RegionPoint point, int32_t dir)
        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();
                }
        }
 
@@ -1128,7 +1117,7 @@ Editor::selected_marker_to_selection_start ()
        Location* loc;
        bool ignored;
 
-       if (!session || selection->markers.empty()) {
+       if (!_session || selection->markers.empty()) {
                return;
        }
 
@@ -1167,7 +1156,7 @@ Editor::selected_marker_to_selection_end ()
        Location* loc;
        bool ignored;
 
-       if (!session || selection->markers.empty()) {
+       if (!_session || selection->markers.empty()) {
                return;
        }
 
@@ -1229,7 +1218,7 @@ Editor::scroll_playhead (bool forward)
                }
        }
 
-       session->request_locate (pos);
+       _session->request_locate (pos);
 }
 
 void
@@ -1244,7 +1233,7 @@ 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;
                }
@@ -1263,7 +1252,7 @@ Editor::playhead_backward ()
           reload, just to move 1 sample !!!
        */
 
-       session->request_locate (pos);
+       _session->request_locate (pos);
 }
 
 void
@@ -1278,7 +1267,7 @@ 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);
                }
@@ -1291,13 +1280,13 @@ Editor::playhead_forward ()
           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;
        }
 
@@ -1307,7 +1296,7 @@ Editor::cursor_align (bool playhead_to_edit)
                        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 */
@@ -1339,7 +1328,7 @@ 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;
                }
@@ -1370,7 +1359,7 @@ 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);
                }
@@ -1392,12 +1381,12 @@ 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
@@ -1413,7 +1402,7 @@ Editor::scroll_backward (float pages)
                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);
                }
@@ -1441,7 +1430,7 @@ Editor::scroll_forward (float pages)
                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);
                }
@@ -1516,7 +1505,7 @@ Editor::scroll_tracks_up_line ()
 void
 Editor::tav_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)
 
        _routes->suspend_redisplay ();
 
@@ -1531,7 +1520,7 @@ Editor::tav_zoom_step (bool coarser)
 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;
 
@@ -1549,7 +1538,7 @@ Editor::temporal_zoom_step (bool coarser)
 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;
@@ -1565,7 +1554,7 @@ 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;
        }
 
@@ -1598,11 +1587,8 @@ Editor::temporal_zoom (gdouble fpu)
                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);
+               /* centre playhead */
+               l = playhead_cursor->current_frame - (new_page_size * 0.5);
 
                if (l < 0) {
                        leftmost_after_zoom = 0;
@@ -1665,7 +1651,7 @@ Editor::temporal_zoom (gdouble fpu)
 
        }
 
-       // 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);
 }
@@ -1754,7 +1740,7 @@ Editor::temporal_zoom_region (bool both_axes)
 
                for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
                        if (find (tracks.begin(), tracks.end(), (*i)) == tracks.end()) {
-                               hide_track_in_display (**i, true);
+                               hide_track_in_display (*i, true);
                        }
                }
 
@@ -1791,17 +1777,23 @@ 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) {
+               nframes_t const l = _session->current_end_frame() - _session->current_start_frame();
+               double s = _session->current_start_frame() - l * 0.01;
+               if (s < 0) {
+                       s = 0;
+               }
+               nframes_t const e = _session->current_end_frame() + l * 0.01;
+               temporal_zoom_by_frame (nframes_t (s), e, "zoom to _session");
        }
 }
 
 void
 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;
@@ -1825,7 +1817,7 @@ Editor::temporal_zoom_by_frame (nframes64_t start, nframes64_t end, const string
 void
 Editor::temporal_zoom_to_frame (bool coarser, nframes64_t frame)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
        double range_before = frame - leftmost_frame;
@@ -1851,8 +1843,8 @@ 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);
@@ -1904,22 +1896,22 @@ 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");
-       Location *location = new Location (start, end, rangename, Location::IsRangeMarker);
+       _session->locations()->next_available_name(rangename,"selection");
+       Location *location = new Location (*_session, 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
@@ -1929,23 +1921,23 @@ 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 ();
+       Location *location = new Location (*_session, 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 ();
 }
 
 void
 Editor::add_location_from_playhead_cursor ()
 {
-       add_location_mark (session->audible_frame());
+       add_location_mark (_session->audible_frame());
 }
 
 void
@@ -1959,23 +1951,21 @@ Editor::add_locations_from_audio_region ()
                return;
        }
 
-       session->begin_reversible_command (rs.size () > 1 ? _("add markers") : _("add marker"));
-       XMLNode &before = session->locations()->get_state();
-
-       cerr << "Add locations\n";
+       _session->begin_reversible_command (rs.size () > 1 ? _("add markers") : _("add marker"));
+       XMLNode &before = _session->locations()->get_state();
 
        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);
+               Location *location = new Location (*_session, 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
@@ -1989,13 +1979,13 @@ 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();
@@ -2006,15 +1996,13 @@ Editor::add_location_from_audio_region ()
                return;
        }
 
-       cerr << "Add location\n";
-
        // single range spanning all selected
-       Location *location = new Location (rs.start(), rs.end_frame(), markername, Location::IsRangeMarker);
-       session->locations()->add (location, true);
+       Location *location = new Location (*_session, rs.start(), rs.end_frame(), markername, Location::IsRangeMarker);
+       _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
@@ -2075,32 +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 ();
        }
 }
 
@@ -2113,66 +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 (*_session, 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();
+       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();
+               Location * looploc = _session->locations()->auto_loop_location();
+               Location * punchloc = _session->locations()->auto_punch_location();
 
-               session->locations()->clear_ranges ();
+               _session->locations()->clear_ranges ();
                // re-add these
-               if (looploc) session->locations()->add (looploc);
-               if (punchloc) session->locations()->add (punchloc);
+               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 ();
+                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
@@ -2209,8 +2197,6 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        boost::shared_ptr<Playlist> playlist;
 
        track_canvas->window_to_world (x, y, wx, wy);
-       //wx += horizontal_adjustment.get_value();
-       //wy += vertical_adjustment.get_value();
 
        GdkEvent event;
        event.type = GDK_BUTTON_RELEASE;
@@ -2240,14 +2226,15 @@ Editor::insert_region_list_drag (boost::shared_ptr<Region> region, int x, int y)
        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 ();
 }
 
 void
-Editor::insert_route_list_drag (boost::shared_ptr<Route> route, int x, int y) {
+Editor::insert_route_list_drag (boost::shared_ptr<Route> route, int x, int y)
+{
        double wx, wy;
        double cx, cy;
        nframes_t where;
@@ -2255,7 +2242,7 @@ Editor::insert_route_list_drag (boost::shared_ptr<Route> route, int x, int y) {
        RouteTimeAxisView *source_rtv = 0;
 
        track_canvas->window_to_world (x, y, wx, wy);
-       wx += horizontal_adjustment.get_value();
+       wx += horizontal_position ();
        wy += vertical_adjustment.get_value();
 
        GdkEvent event;
@@ -2318,9 +2305,9 @@ Editor::insert_region_list_selection (float times)
        }
 
        begin_reversible_command (_("insert region"));
-       XMLNode &before = playlist->get_state();
+        playlist->clear_history ();
        playlist->add_region ((RegionFactory::create (region)), get_preferred_edit_position(), times);
-       session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
+       _session->add_command(new StatefulDiffCommand (playlist));
        commit_reversible_command ();
 }
 
@@ -2344,12 +2331,12 @@ Editor::edit_envelope ()
 void
 Editor::transition_to_rolling (bool fwd)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
-       if (session->config.get_external_sync()) {
-               switch (session->config.get_sync_source()) {
+       if (_session->config.get_external_sync()) {
+               switch (_session->config.get_sync_source()) {
                case JACK:
                        break;
                default:
@@ -2358,24 +2345,24 @@ Editor::transition_to_rolling (bool fwd)
                }
        }
 
-       if (session->is_auditioning()) {
-               session->cancel_audition ();
+       if (_session->is_auditioning()) {
+               _session->cancel_audition ();
                return;
        }
 
-       session->request_transport_speed (fwd ? 1.0f : -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
@@ -2386,19 +2373,19 @@ 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);
        }
 }
 
@@ -2409,7 +2396,7 @@ Editor::play_selection ()
                return;
        }
 
-       session->request_play_range (&selection->time, true);
+       _session->request_play_range (&selection->time, true);
 }
 
 void
@@ -2429,9 +2416,9 @@ Editor::loop_selected_region ()
 
                        // 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);
                }
        }
 }
@@ -2443,7 +2430,7 @@ Editor::play_location (Location& location)
                return;
        }
 
-       session->request_bounded_roll (location.start(), location.end());
+       _session->request_bounded_roll (location.start(), location.end());
 }
 
 void
@@ -2459,8 +2446,8 @@ 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);
        }
 }
 
@@ -2525,8 +2512,8 @@ 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);
@@ -2534,7 +2521,7 @@ 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 ();
 
@@ -2557,8 +2544,8 @@ 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
@@ -2568,7 +2555,7 @@ Editor::audition_playlist_region_via_route (boost::shared_ptr<Region> region, Ro
 
        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 ? */
 }
@@ -2580,7 +2567,7 @@ 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);
        }
 }
 
@@ -2606,46 +2593,13 @@ Editor::play_selected_region ()
                }
        }
 
-       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
@@ -2662,7 +2616,7 @@ Editor::region_from_selection ()
        nframes64_t start = selection->time[clicked_selection].start;
        nframes64_t end = selection->time[clicked_selection].end;
 
-       TrackSelection tracks = get_tracks_for_range_action ();
+       TrackViewList tracks = get_tracks_for_range_action ();
 
        nframes64_t selection_cnt = end - start + 1;
 
@@ -2681,9 +2635,16 @@ 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));
        }
 }
 
@@ -2714,10 +2675,15 @@ 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);
+
+               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,
-                                       internal_start, end - start + 1, new_name));
+               new_regions.push_back (RegionFactory::create (current, plist));
        }
 }
 
@@ -2735,7 +2701,7 @@ 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);
        }
 }
 
@@ -2763,10 +2729,10 @@ add_if_covered (RegionView* rv, const AudioRange* ar, RegionSelection* rs)
  *    - all tracks
  * @return tracks.
  */
-TrackSelection
+TrackViewList
 Editor::get_tracks_for_range_action () const
 {
-       TrackSelection t;
+       TrackViewList t;
 
        if (selection->tracks.empty()) {
 
@@ -2802,7 +2768,7 @@ Editor::separate_regions_between (const TimeSelection& ts)
        boost::shared_ptr<Playlist> playlist;
        RegionSelection new_selection;
 
-       TrackSelection tmptracks = get_tracks_for_range_action ();
+       TrackViewList tmptracks = get_tracks_for_range_action ();
        sort_track_selection (&tmptracks);
 
        for (TrackSelection::iterator i = tmptracks.begin(); i != tmptracks.end(); ++i) {
@@ -2815,54 +2781,55 @@ 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;
-
-                                       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),
-                                                               (nframes64_t)((*t).end * speed), true);
+                                                               (nframes64_t)((*t).end * speed), false);
 
                                                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;
                                                        }
+                                                        
+                                                        /* pick up changes to existing regions */
 
-                                                       session->add_command(new MementoCommand<Playlist>(
-                                                                       *playlist, before, &playlist->get_state()));
-                                               }
-                                       }
+                                                        vector<StatefulDiffCommand*> cmds;
+                                                        playlist->rdiff (cmds);
+                                                        for (vector<StatefulDiffCommand*>::iterator j = cmds.begin(); j != cmds.end(); ++j) {
+                                                                _session->add_command (*j);
+                                                        }
 
-                                       if (!got_some) {
-                                               delete before;
+                                                        /* pick up changes to the playlist itself (adds/removes)
+                                                         */
+
+                                                       _session->add_command(new StatefulDiffCommand (playlist));
+                                               }
                                        }
                                }
                        }
@@ -2877,6 +2844,11 @@ Editor::separate_regions_between (const TimeSelection& ts)
        }
 }
 
+struct PlaylistState {
+    boost::shared_ptr<Playlist> playlist;
+    XMLNode*  before;
+};
+
 /** 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.
@@ -2912,7 +2884,7 @@ 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);
        }
@@ -2921,7 +2893,7 @@ 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);
        }
@@ -2942,6 +2914,85 @@ Editor::separate_regions_using_location (Location& loc)
        separate_regions_between (ts);
 }
 
+/** Separate regions under the selected region */
+void
+Editor::separate_under_selected_regions ()
+{
+       RegionSelection rs;
+       get_regions_for_action (rs);
+       
+       vector<PlaylistState> playlists;
+
+       if (!_session) {
+               return;
+       }
+
+       if (rs.empty()) {
+               return;
+       }
+
+       begin_reversible_command (_("separate region under"));
+
+       list<boost::shared_ptr<Region> > regions_to_remove;
+
+       for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
+               // we can't just remove the region(s) in this loop because
+               // this removes them from the RegionSelection, and they thus
+               // disappear from underneath the iterator, and the ++i above
+               // SEGVs in a puzzling fashion.
+
+               // 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());
+       }
+
+       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();
+
+               if (!playlist) {
+                       // is this check necessary?
+                       continue;
+               }
+
+               vector<PlaylistState>::iterator i;
+
+               //only take state if this is a new playlist.
+               for (i = playlists.begin(); i != playlists.end(); ++i) {
+                       if ((*i).playlist == playlist) {
+                               break;
+                       }
+               }
+
+               if (i == playlists.end()) {
+
+                       PlaylistState before;
+                       before.playlist = playlist;
+                       before.before = &playlist->get_state();
+
+                       playlist->freeze ();
+                       playlists.push_back(before);
+               }
+
+               //Partition on the region bounds
+               playlist->partition ((*rl)->first_frame() - 1, (*rl)->last_frame() + 1, true);
+               
+               //Re-add region that was just removed due to the partition operation
+               playlist->add_region( (*rl), (*rl)->first_frame() );
+       }
+
+       vector<PlaylistState>::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()));
+       }
+
+       commit_reversible_command ();
+}
+
 void
 Editor::crop_region_to_selection ()
 {
@@ -2966,7 +3017,7 @@ 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;
@@ -2983,7 +3034,7 @@ Editor::crop_region_to (nframes64_t start, nframes64_t end)
 
                        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);
@@ -3025,10 +3076,9 @@ 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 ();
@@ -3042,11 +3092,11 @@ Editor::region_fill_track ()
 
        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"));
 
@@ -3066,9 +3116,9 @@ Editor::region_fill_track ()
                        return;
                }
 
-               XMLNode &before = pl->get_state();
+                pl->clear_history ();
                pl->add_region (RegionFactory::create (region), region->last_frame(), times);
-               session->add_command (new MementoCommand<Playlist>(*pl, &before, &pl->get_state()));
+               _session->add_command (new StatefulDiffCommand (pl));
        }
 
        commit_reversible_command ();
@@ -3110,9 +3160,9 @@ Editor::region_fill_selection ()
                        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 ();
@@ -3145,10 +3195,9 @@ Editor::set_sync_point (nframes64_t where, const RegionSelection& rs)
                        in_command = true;
                }
 
-               XMLNode &before = region->playlist()->get_state();
+                region->clear_history ();
                region->set_sync_position (where);
-               XMLNode &after = region->playlist()->get_state();
-               session->add_command(new MementoCommand<Playlist>(*(region->playlist()), &before, &after));
+               _session->add_command(new StatefulDiffCommand (region));
        }
 
        if (in_command) {
@@ -3171,10 +3220,9 @@ 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 ();
 }
@@ -3192,10 +3240,9 @@ 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 ();
 }
@@ -3294,10 +3341,9 @@ 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 */
 
@@ -3307,16 +3353,15 @@ Editor::align_selection_relative (RegionPoint point, nframes64_t position, const
 
                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));
 
        }
 
@@ -3350,7 +3395,7 @@ 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:
@@ -3368,8 +3413,7 @@ 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
@@ -3400,15 +3444,16 @@ 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);
                        } else {
                                (*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()));
                }
        }
 
@@ -3419,7 +3464,7 @@ 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;
        }
@@ -3429,7 +3474,7 @@ 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;
        }
@@ -3464,18 +3509,16 @@ 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 ();
@@ -3507,15 +3550,13 @@ 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 ();
@@ -3547,15 +3588,13 @@ 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 ();
@@ -3600,15 +3639,15 @@ 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){
 
@@ -3618,8 +3657,8 @@ Editor::trim_to_region(bool forward)
                        continue;
                    }
 
-                   region->trim_end((nframes64_t) (next_region->first_frame() * speed), this);
-                   arv->region_changed (Change (LengthChanged));
+                   region->trim_end((nframes64_t) ( (next_region->first_frame() - 1) * speed), this);
+                   arv->region_changed (PropertyChange (ARDOUR::Properties::length));
                }
                else {
 
@@ -3630,11 +3669,11 @@ Editor::trim_to_region(bool forward)
                    }
 
                    region->trim_front((nframes64_t) ((next_region->last_frame() + 1) * speed), this);
-                   arv->region_changed (Change (LengthChanged|PositionChanged|StartChanged));
+
+                   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 ();
@@ -3653,7 +3692,6 @@ Editor::unfreeze_route ()
 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 ();
@@ -3662,18 +3700,11 @@ Editor::_freeze_thread (void* arg)
 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 ()
 {
@@ -3682,33 +3713,11 @@ Editor::freeze_route ()
        }
 
        InterThreadInfo itt;
-
-       if (interthread_progress_window == 0) {
-               build_interthread_progress_window ();
-       }
-
-       interthread_progress_window->set_title (_("Freeze"));
-       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"));
        current_interthread_info = &itt;
 
-       interthread_progress_connection =
-         Glib::signal_timeout().connect (bind (mem_fun(*this, &Editor::freeze_progress_timeout), (gpointer) 0), 100);
-
-       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);
+       InterthreadProgressWindow ipw (current_interthread_info, _("Freeze"), _("Cancel Freeze"));
 
-       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));
 
@@ -3716,8 +3725,6 @@ 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);
 }
@@ -3753,11 +3760,9 @@ Editor::bounce_range_selection (bool replace, bool enable_processing)
 
                InterThreadInfo itt;
 
-               itt.done = false;
-               itt.cancel = false;
-               itt.progress = false;
-
-                XMLNode &before = playlist->get_state();
+                playlist->clear_history ();
+               playlist->clear_owned_history ();
+               
                boost::shared_ptr<Region> r = rtv->track()->bounce_range (start, start+cnt, itt, enable_processing);
 
                if (replace) {
@@ -3767,8 +3772,13 @@ 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));
+               vector<StatefulDiffCommand*> cmds;
+               playlist->rdiff (cmds);
+               for (vector<StatefulDiffCommand*>::iterator j = cmds.begin(); j != cmds.end(); ++j) {
+                       _session->add_command (*j);
+               }
+
+                _session->add_command (new StatefulDiffCommand (playlist));
        }
 
        commit_reversible_command ();
@@ -3844,10 +3854,8 @@ 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 ();
                }
        }
 
@@ -3860,14 +3868,11 @@ 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->abort ();
                return;
        }
 
@@ -3929,7 +3934,7 @@ Editor::cut_copy (CutCopyOp op)
                                if (!get_edit_op_range (start, end)) {
                                        return;
                                }
-                               selection->set ((TimeAxisView*) 0, start, end);
+                               selection->set (start, end);
                        }
 
                        begin_reversible_command (opname + _(" range"));
@@ -3948,9 +3953,7 @@ Editor::cut_copy (CutCopyOp op)
        }
 
        if (op == Cut || op == Clear) {
-               break_drag ();
-               delete _drag;
-               _drag = 0;
+               _drags->abort ();
        }
 }
 
@@ -3962,7 +3965,7 @@ 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);
@@ -3982,10 +3985,7 @@ Editor::cut_copy_midi (CutCopyOp op)
        }
 }
 
-struct PlaylistState {
-    boost::shared_ptr<Playlist> playlist;
-    XMLNode*  before;
-};
+
 
 struct lt_playlist {
     bool operator () (const PlaylistState& a, const PlaylistState& b) {
@@ -4011,10 +4011,9 @@ 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 ();
 }
 
@@ -4026,7 +4025,7 @@ Editor::remove_selected_regions ()
        RegionSelection rs;
        get_regions_for_action (rs);
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4051,7 +4050,7 @@ Editor::remove_selected_regions ()
                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) {
 
@@ -4062,33 +4061,31 @@ 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);
        }
 
-       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 ();
@@ -4108,8 +4105,8 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
 
        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 */
 
@@ -4123,21 +4120,19 @@ 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);
                                }
                        }
                }
@@ -4183,7 +4178,7 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
                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 {
@@ -4228,18 +4223,18 @@ Editor::cut_copy_regions (CutCopyOp op, RegionSelection& rs)
        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) {
@@ -4297,8 +4292,8 @@ 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 */
@@ -4365,12 +4360,12 @@ 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, end_frame + (r->first_frame() - start_frame) + 1, 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), times);
+               _session->add_command(new StatefulDiffCommand (playlist));
 
                c.disconnect ();
 
@@ -4409,10 +4404,9 @@ 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()) {
@@ -4430,7 +4424,7 @@ Editor::reset_point_selection ()
 
        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);
@@ -4456,10 +4450,9 @@ 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 ();
 }
 
@@ -4493,10 +4486,20 @@ Editor::nudge_track (bool use_edit, bool forwards)
                        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 ();
@@ -4508,7 +4511,7 @@ Editor::remove_last_capture ()
        vector<string> choices;
        string prompt;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4519,21 +4522,23 @@ 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 ();
+                        _regions->redisplay ();
                }
 
        } else {
-               session->remove_last_capture();
+               _session->remove_last_capture();
+                _regions->redisplay ();
        }
 }
 
 void
 Editor::normalize_region ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4546,6 +4551,8 @@ Editor::normalize_region ()
 
        Dialog dialog (rs.size() > 1 ? _("Normalize regions") : _("Normalize region"));
        HBox hbox;
+       hbox.set_spacing (6);
+       hbox.set_border_width (6);
        hbox.pack_start (*manage (new Label (_("Normalize to:"))));
        SpinButton spin (0.2, 2);
        spin.set_range (-112, 0);
@@ -4555,6 +4562,7 @@ Editor::normalize_region ()
        spin.set_value (_last_normalization_value);
        hbox.pack_start (*manage (new Label (_("dbFS"))));
        hbox.show_all ();
+       dialog.get_vbox()->set_spacing (12);
        dialog.get_vbox()->pack_start (hbox);
        dialog.add_button (Stock::CANCEL, RESPONSE_CANCEL);
        dialog.add_button (_("Normalize"), RESPONSE_ACCEPT);
@@ -4572,9 +4580,10 @@ Editor::normalize_region ()
                AudioRegionView* const arv = dynamic_cast<AudioRegionView*>(*r);
                if (!arv)
                        continue;
-               XMLNode &before = arv->region()->get_state();
+                arv->region()->clear_history ();
                arv->audio_region()->normalize_to (spin.get_value());
-               session->add_command (new MementoCommand<Region>(*(arv->region().get()), &before, &arv->region()->get_state()));
+               _session->add_command (new StatefulDiffCommand (arv->region()));
+                                       
        }
 
        commit_reversible_command ();
@@ -4587,7 +4596,7 @@ Editor::normalize_region ()
 void
 Editor::reset_region_scale_amplitude ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4605,9 +4614,9 @@ Editor::reset_region_scale_amplitude ()
                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 ();
@@ -4616,7 +4625,7 @@ Editor::reset_region_scale_amplitude ()
 void
 Editor::adjust_region_scale_amplitude (bool up)
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4632,10 +4641,12 @@ 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) {
@@ -4657,7 +4668,7 @@ Editor::adjust_region_scale_amplitude (bool up)
                }
 
                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 ();
@@ -4667,18 +4678,18 @@ 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;
        }
 
@@ -4698,11 +4709,11 @@ Editor::strip_region_silence ()
                }
        }
 
-       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"));
        }
 }
@@ -4711,7 +4722,7 @@ Command*
 Editor::apply_midi_note_edit_op_to_region (MidiOperator& op, MidiRegionView& mrv)
 {
        Evoral::Sequence<Evoral::MusicalTime>::Notes selected;
-       mrv.selection_as_notelist (selected);
+       mrv.selection_as_notelist (selected, true);
 
        vector<Evoral::Sequence<Evoral::MusicalTime>::Notes> v;
        v.push_back (selected);
@@ -4743,7 +4754,7 @@ Editor::apply_midi_note_edit_op (MidiOperator& op)
                        cmd = apply_midi_note_edit_op_to_region (op, *mrv);
                        if (cmd) {
                                (*cmd)();
-                               session->add_command (cmd);
+                               _session->add_command (cmd);
                        }
                }
 
@@ -4754,10 +4765,50 @@ Editor::apply_midi_note_edit_op (MidiOperator& op)
        rs.clear ();
 }
 
+void
+Editor::fork_region ()
+{
+       RegionSelection rs;
+
+       get_regions_for_action (rs);
+
+       if (rs.empty()) {
+               return;
+       }
+
+       begin_reversible_command (_("Fork Region(s)"));
+
+       track_canvas->get_window()->set_cursor (*wait_cursor);
+       gdk_flush ();
+
+       for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ) {
+               RegionSelection::iterator tmp = r;
+               ++tmp;
+
+               MidiRegionView* const mrv = dynamic_cast<MidiRegionView*>(*r);
+
+               if (mrv) {
+                       boost::shared_ptr<Playlist> playlist = mrv->region()->playlist();
+                        boost::shared_ptr<MidiRegion> newregion = mrv->midi_region()->clone ();
+                        
+                        playlist->clear_history ();
+                        playlist->replace_region (mrv->region(), newregion, mrv->region()->position());
+                        _session->add_command(new StatefulDiffCommand (playlist));
+               }
+
+               r = tmp;
+       }
+
+       commit_reversible_command ();
+       rs.clear ();
+
+       track_canvas->get_window()->set_cursor (*current_canvas_cursor);
+}
+
 void
 Editor::quantize_region ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -4768,7 +4819,7 @@ Editor::quantize_region ()
        qd->hide ();
 
        if (r == Gtk::RESPONSE_OK) {
-               Quantize quant (*session, Plain,
+               Quantize quant (*_session, Plain,
                                qd->snap_start(), qd->snap_end(),
                                qd->start_grid_size(), qd->end_grid_size(),
                                qd->strength(), qd->swing(), qd->threshold());
@@ -4803,8 +4854,8 @@ Editor::apply_filter (Filter& filter, string command)
 
                        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 */
@@ -4826,8 +4877,7 @@ Editor::apply_filter (Filter& filter, string command)
 
                                }
 
-                               XMLNode &after = playlist->get_state();
-                               session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
+                               _session->add_command(new StatefulDiffCommand (playlist));
                        } else {
                                goto out;
                        }
@@ -4899,13 +4949,13 @@ Editor::brush (nframes64_t pos)
 void
 Editor::reset_region_gain_envelopes ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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);
@@ -4914,144 +4964,139 @@ 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 = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region gain envelope visible"));
+       _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) {
-                       XMLNode &before = arv->region()->get_state ();
+                        arv->region()->clear_history ();
                        arv->set_envelope_visible (!arv->envelope_visible());
-                       XMLNode &after = arv->region()->get_state ();
-                       session->add_command (new MementoCommand<Region> (*(arv->region().get()), &before, &after));
+                       _session->add_command (new StatefulDiffCommand (arv->region()));
                }
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_gain_envelope_active ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region gain envelope active"));
+       _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) {
-                       XMLNode &before = arv->region()->get_state ();
+                       arv->region()->clear_history ();
                        arv->audio_region()->set_envelope_active (!arv->audio_region()->envelope_active());
-                       XMLNode &after = arv->region()->get_state ();
-                       session->add_command (new MementoCommand<Region> (*(arv->region().get()), &before, &after));
+                       _session->add_command (new StatefulDiffCommand (arv->region()));
                }
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_region_lock ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region lock"));
+       _session->begin_reversible_command (_("region lock"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
-               XMLNode &before = (*i)->region()->get_state ();
+               (*i)->region()->clear_history ();
                (*i)->region()->set_locked (!(*i)->region()->locked());
-               XMLNode &after = (*i)->region()->get_state ();
-               session->add_command (new MementoCommand<Region> (*((*i)->region().get()), &before, &after));
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
-Editor::set_region_lock_style (Region::PositionLockStyle ps)
+Editor::toggle_region_lock_style ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region lock style"));
+       _session->begin_reversible_command (_("region lock style"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
-               XMLNode &before = (*i)->region()->get_state ();
-               (*i)->region()->set_position_lock_style (ps);
-               XMLNode &after = (*i)->region()->get_state ();
-               session->add_command (new MementoCommand<Region> (*((*i)->region().get()), &before, &after));
+                (*i)->region()->clear_history ();
+               PositionLockStyle const ns = (*i)->region()->position_lock_style() == AudioTime ? MusicTime : AudioTime;
+               (*i)->region()->set_position_lock_style (ns);
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 
 void
 Editor::toggle_region_mute ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region mute"));
+       _session->begin_reversible_command (_("region mute"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
-               XMLNode &before = (*i)->region()->get_state ();
+               (*i)->region()->clear_history ();
                (*i)->region()->set_muted (!(*i)->region()->muted());
-               XMLNode &after = (*i)->region()->get_state ();
-               session->add_command (new MementoCommand<Region> (*((*i)->region().get()), &before, &after));
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
 Editor::toggle_region_opaque ()
 {
-       RegionSelection rs = get_equivalent_regions (selection->regions, RouteGroup::Edit);
+       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 (_("region opacity"));
+       _session->begin_reversible_command (_("region opacity"));
 
        for (RegionSelection::iterator i = rs.begin(); i != rs.end(); ++i) {
-               XMLNode &before = (*i)->region()->get_state ();
+               (*i)->region()->clear_history ();
                (*i)->region()->set_opaque (!(*i)->region()->opaque());
-               XMLNode &after = (*i)->region()->get_state ();
-               session->add_command (new MementoCommand<Region> (*((*i)->region().get()), &before, &after));
+               _session->add_command (new StatefulDiffCommand ((*i)->region()));
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 }
 
 void
@@ -5071,7 +5116,7 @@ Editor::toggle_record_enable ()
                        first = false;
                }
 
-               rtav->track()->set_record_enable(new_state, this);
+               rtav->track()->set_record_enable(new_state, this);
        }
 }
 
@@ -5093,7 +5138,7 @@ Editor::set_fade_length (bool in)
 
        nframes64_t pos = get_preferred_edit_position();
        nframes64_t len;
-       char* cmd;
+       char const * cmd;
 
        if (pos > rv->region()->last_frame() || pos < rv->region()->first_frame()) {
                /* edit point is outside the relevant region */
@@ -5143,7 +5188,7 @@ Editor::set_fade_length (bool in)
                }
 
                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 ();
@@ -5186,14 +5231,15 @@ 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 ();
@@ -5225,7 +5271,7 @@ Editor::set_fade_in_shape (AudioRegion::FadeShape shape)
                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 ();
@@ -5258,7 +5304,7 @@ Editor::set_fade_out_shape (AudioRegion::FadeShape shape)
                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 ();
@@ -5286,13 +5332,10 @@ Editor::set_fade_in_active (bool yn)
 
 
                boost::shared_ptr<AudioRegion> ar (tmp->audio_region());
-
-               XMLNode &before = ar->get_state();
-
+               
+                ar->clear_history ();
                ar->set_fade_in_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 ();
@@ -5320,12 +5363,9 @@ 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 ();
@@ -5381,7 +5421,7 @@ 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);
@@ -5399,7 +5439,7 @@ 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);
@@ -5444,7 +5484,7 @@ 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;
@@ -5455,8 +5495,8 @@ Editor::set_playhead_cursor ()
 
                snap_to (where);
 
-               if (session) {
-                       session->request_locate (where, session->transport_rolling());
+               if (_session) {
+                       _session->request_locate (where, _session->transport_rolling());
                }
        }
 }
@@ -5464,6 +5504,13 @@ Editor::set_playhead_cursor ()
 void
 Editor::split ()
 {
+        if (((mouse_mode == MouseRange) || 
+             (mouse_mode != MouseObject && _join_object_range_state == JOIN_OBJECT_RANGE_RANGE)) && 
+            !selection->time.empty()) {
+                separate_regions_between (selection->time);
+                return;
+        } 
+
        RegionSelection rs;
 
        get_regions_for_action (rs, true);
@@ -5598,7 +5645,7 @@ 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;
        }
 
@@ -5608,15 +5655,15 @@ Editor::set_loop_from_selection (bool play)
        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;
        }
 
@@ -5630,8 +5677,8 @@ 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);
        }
 }
 
@@ -5661,15 +5708,15 @@ 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;
        }
 
@@ -5682,7 +5729,7 @@ Editor::set_punch_from_selection ()
 void
 Editor::set_punch_from_edit_range ()
 {
-       if (session == 0) {
+       if (_session == 0) {
                return;
        }
 
@@ -5739,7 +5786,7 @@ Editor::pitch_shift_regions ()
 void
 Editor::use_region_as_bar ()
 {
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -5770,7 +5817,7 @@ 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 */
 
@@ -5782,7 +5829,7 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
 
        /* 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:
 
@@ -5791,11 +5838,11 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
 
        */
 
-       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
@@ -5805,8 +5852,13 @@ 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()) {
@@ -5830,19 +5882,19 @@ Editor::define_one_bar (nframes64_t start, nframes64_t end)
        }
 
        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 ();
 }
 
@@ -5851,7 +5903,7 @@ Editor::split_region_at_transients ()
 {
        AnalysisFeatureList positions;
 
-       if (!session) {
+       if (!_session) {
                return;
        }
 
@@ -5863,7 +5915,7 @@ 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(); ) {
 
@@ -5882,7 +5934,7 @@ Editor::split_region_at_transients ()
                i = tmp;
        }
 
-       session->commit_reversible_command ();
+       _session->commit_reversible_command ();
 
 }
 
@@ -5921,6 +5973,7 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
 
                int response = msg.run();
                msg.hide ();
+               
                switch (response) {
                case RESPONSE_OK:
                        break;
@@ -5939,19 +5992,10 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
 
        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;
        }
@@ -5959,18 +6003,26 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
        pl->freeze ();
        pl->remove_region (r);
 
+       nframes64_t pos = 0;
+
        while (x != positions.end()) {
+         
+               /* deal with positons that are out of scope of present region bounds */
+               if (*x <= 0 || *x > r->length()){
+                       ++x;
+                       continue;
+               }
 
                /* file start = original start + how far we from the initial position ?
                 */
 
-               nframes64_t file_start = r->start() + (pos - r->position());
+               nframes64_t file_start = r->start() + pos;
 
                /* length = next position - current position
                 */
 
                nframes64_t len = (*x) - pos;
-
+               
                /* XXX we do we really want to allow even single-sample regions?
                   shouldn't we have some kind of lower limit on region size?
                */
@@ -5981,37 +6033,204 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
 
                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);
-               pl->add_region (nr, pos);
+               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, r->position() + pos);
 
                pos += len;
                ++x;
+       }
 
-               if (*x > r->last_frame()) {
+       string new_name;
 
-                       /* add final fragment */
+       RegionFactory::region_name (new_name, r->name());
+       
+       /* Add the final region */
+       PropertyList plist; 
+               
+       plist.add (ARDOUR::Properties::start, r->start() + pos);
+       plist.add (ARDOUR::Properties::length, r->last_frame() - (r->position() + pos) + 1);
+       plist.add (ARDOUR::Properties::name, new_name);
+       plist.add (ARDOUR::Properties::layer, 0);
 
-                       file_start = r->start() + (pos - r->position());
-                       len = r->last_frame() - pos;
+       boost::shared_ptr<Region> nr = RegionFactory::create (r->sources(), plist, false);
+       pl->add_region (nr, r->position() + pos);
 
-                       nr = RegionFactory::create (r->sources(), file_start, len, new_name, 0, Region::DefaultFlags);
-                       pl->add_region (nr, pos);
+       
+       pl->thaw ();
 
-                       break;
-               }
+       _session->add_command (new StatefulDiffCommand (pl));
+}
+
+void
+Editor::place_transient()
+{
+       if (!_session) {
+               return;
        }
 
-       pl->thaw ();
+       RegionSelection rs;
 
-       XMLNode& after (pl->get_state());
+       get_regions_for_action (rs);
 
-       session->add_command (new MementoCommand<Playlist>(*pl, &before, &after));
+       if (rs.empty()) {
+               return;
+       }
+       
+       nframes64_t where = get_preferred_edit_position();
+
+       _session->begin_reversible_command (_("place transient"));
+       
+       for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
+               framepos_t position = (*r)->region()->position();
+               (*r)->region()->add_transient(where - position);
+       }
+       
+       _session->commit_reversible_command ();
+}
+
+void
+Editor::remove_transient(ArdourCanvas::Item* item)
+{
+       if (!_session) {
+               return;
+       }
+
+       ArdourCanvas::SimpleLine* _line = reinterpret_cast<ArdourCanvas::SimpleLine*> (item);
+       assert (_line);
+
+       AudioRegionView* _arv = reinterpret_cast<AudioRegionView*> (item->get_data ("regionview"));
+       _arv->remove_transient(_line->property_x1());
+}
+
+void
+Editor::snap_regions_to_grid()
+{
+       if (!_session) {
+               return;
+       }
+
+       RegionSelection rs;
+
+       get_regions_for_action (rs);
+
+       if (rs.empty()) {
+               return;
+       }
+       
+       _session->begin_reversible_command (_("snap regions to grid"));
+       
+       for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
+               framepos_t start_frame = (*r)->region()->first_frame ();
+               snap_to (start_frame);
+               (*r)->region()->set_position (start_frame, this);
+       }
+       
+       _session->commit_reversible_command ();
+}
+
+void
+Editor::close_region_gaps()
+{      
+       if (!_session) {
+               return;
+       }
+
+       RegionSelection rs;
+
+       get_regions_for_action (rs);
+       
+       if (rs.empty()) {
+               return;
+       }
+       
+       Dialog dialog (rs.size() > 1 ? _("Conform regions") : _("Conform region"));
+       
+       HBox hbox_crossfade;
+       hbox_crossfade.set_spacing (10);
+       //hbox_crossfade.set_border_width (3);
+       hbox_crossfade.pack_start (*manage (new Label (_("Crossfade length:"))));
+       
+       SpinButton spin_crossfade (1, 0);
+       spin_crossfade.set_range (0, 15);
+       spin_crossfade.set_increments (1, 1);
+       spin_crossfade.set_value (3);
+       
+       hbox_crossfade.pack_start (spin_crossfade);
+       hbox_crossfade.pack_start (*manage (new Label (_("ms"))));
+       hbox_crossfade.show_all ();
+
+       HBox hbox_pullback;
+       
+       hbox_pullback.set_spacing (10);
+       //hbox_pullback.set_border_width (3);
+       hbox_pullback.pack_start (*manage (new Label (_("Pull-back length:"))));
+       
+       SpinButton spin_pullback (1, 0);
+       spin_pullback.set_range (0, 15);
+       spin_pullback.set_increments (1, 1);
+       spin_pullback.set_value (5);
+       
+       hbox_pullback.pack_start (spin_pullback);
+       hbox_pullback.pack_start (*manage (new Label (_("ms"))));
+       hbox_pullback.show_all ();
+       
+       dialog.get_vbox()->set_spacing (6);
+       dialog.get_vbox()->pack_start (hbox_crossfade);
+       dialog.get_vbox()->pack_start (hbox_pullback);
+       dialog.add_button (Stock::CANCEL, RESPONSE_CANCEL);
+       dialog.add_button (_("Ok"), RESPONSE_ACCEPT);
+
+       if (dialog.run () == RESPONSE_CANCEL) {
+               return;
+       }
+
+       nframes64_t crossfade_len  = spin_crossfade.get_value(); 
+       nframes64_t pull_back_frames = spin_pullback.get_value();
+
+       crossfade_len = lrintf (crossfade_len * _session->frame_rate()/1000);
+       pull_back_frames = lrintf (pull_back_frames * _session->frame_rate()/1000);
+
+       /* Iterate over the region list and make adjacent regions overlap by crossfade_len_ms */
+       
+       _session->begin_reversible_command (_("close region gaps"));
+               
+       int idx = 0;
+       boost::shared_ptr<Region> last_region;
+       
+       rs.sort_by_position_and_track();
+       
+       for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
+
+               nframes64_t position = (*r)->region()->position();
+         
+               if (idx == 0 || position < last_region->position()){
+                       last_region = (*r)->region();
+                       idx++;
+                       continue;
+               }
+               
+               (*r)->region()->trim_front( (position - pull_back_frames), this );
+               last_region->trim_end( (position - pull_back_frames + crossfade_len), this );
+               
+               last_region = (*r)->region();
+               
+               idx++;
+       }
+       
+       _session->commit_reversible_command ();
 }
 
 void
@@ -6019,11 +6238,11 @@ 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()) {
 
@@ -6032,9 +6251,9 @@ 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);
 
@@ -6061,7 +6280,7 @@ Editor::tab_to_transient (bool forward)
                }
        }
 
-       TransientDetector::cleanup_transients (positions, session->frame_rate(), 3.0);
+       TransientDetector::cleanup_transients (positions, _session->frame_rate(), 3.0);
 
        if (forward) {
                AnalysisFeatureList::iterator x;
@@ -6073,7 +6292,7 @@ Editor::tab_to_transient (bool forward)
                }
 
                if (x != positions.end ()) {
-                       session->request_locate (*x);
+                       _session->request_locate (*x);
                }
 
        } else {
@@ -6086,19 +6305,20 @@ 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);
        }
 }
 
@@ -6106,17 +6326,17 @@ 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);
        }
 }
 
 void
-Editor::set_track_height (uint32_t h)
+Editor::set_track_height (Height h)
 {
        TrackSelection& ts (selection->tracks);
 
@@ -6165,6 +6385,7 @@ Editor::remove_tracks ()
        const char* trackstr;
        const char* busstr;
        vector<boost::shared_ptr<Route> > routes;
+        bool special_bus = false;
 
        for (TrackSelection::iterator x = ts.begin(); x != ts.end(); ++x) {
                RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (*x);
@@ -6176,8 +6397,30 @@ Editor::remove_tracks ()
                        }
                }
                routes.push_back (rtv->_route);
-       }
 
+                if (rtv->route()->is_master() || rtv->route()->is_monitor()) {
+                        special_bus = true;
+                }
+        }
+
+        if (special_bus && !Config->get_allow_special_bus_removal()) {
+                MessageDialog msg (_("That would be bad news ...."),
+                                   false,
+                                   Gtk::MESSAGE_INFO,
+                                   Gtk::BUTTONS_OK);
+                msg.set_secondary_text (string_compose (_(
+"Removing the master or monitor bus is such a bad idea\n\
+that %1 is not going to allow it.\n\
+\n\
+If you really want to do this sort of thing\n\
+edit your ardour.rc file to set the\n\
+\"allow-special-bus-removal\" option to be \"yes\""), PROGRAM_NAME));
+
+                msg.present ();
+                msg.run ();
+                return;
+        }
+                
        if (ntracks + nbusses == 0) {
                return;
        }
@@ -6218,14 +6461,21 @@ 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);
        }
 }
 
@@ -6251,7 +6501,7 @@ Editor::do_insert_time ()
        table.attach (time_label, 0, 1, 0, 1, FILL | EXPAND);
        AudioClock clock ("insertTimeClock", true, X_("InsertTimeClock"), true, false, true, true);
        clock.set (0);
-       clock.set_session (session);
+       clock.set_session (_session);
        clock.set_bbt_reference (pos);
        table.attach (clock, 1, 2, 0, 1);
 
@@ -6290,7 +6540,8 @@ Editor::do_insert_time ()
                return;
        }
 
-       InsertTimeOption opt;
+       /* only setting this to keep GCC quiet */
+       InsertTimeOption opt = LeaveIntersected;
 
        switch (intersected_combo.get_active_row_number ()) {
        case 0:
@@ -6325,7 +6576,8 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
 
                if (pl) {
 
-                       XMLNode &before = pl->get_state();
+                       pl->clear_history ();
+                        pl->clear_owned_history ();
 
                        if (opt == SplitIntersected) {
                                pl->split (pos);
@@ -6333,9 +6585,15 @@ Editor::insert_time (nframes64_t pos, nframes64_t frames, InsertTimeOption opt,
 
                        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);
+                        
+                        for (vector<StatefulDiffCommand*>::iterator c = cmds.begin(); c != cmds.end(); ++c) {
+                                _session->add_command (*c);
+                        }
+                        
+                       _session->add_command (new StatefulDiffCommand (pl));
                        commit = true;
                }
 
@@ -6350,8 +6608,8 @@ 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) {
 
@@ -6367,13 +6625,13 @@ 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) {
@@ -6388,7 +6646,7 @@ Editor::fit_selected_tracks ()
 }
 
 void
-Editor::fit_tracks (TrackSelection & tracks)
+Editor::fit_tracks (TrackViewList & tracks)
 {
        if (tracks.empty()) {
                return;
@@ -6408,7 +6666,7 @@ Editor::fit_tracks (TrackSelection & tracks)
        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) {
+       if (h < TimeAxisView::preset_height (HeightSmall)) {
                MessageDialog msg (*this, _("There are too many tracks to fit in the current window"));
                /* too small to be displayed */
                return;
@@ -6440,7 +6698,7 @@ Editor::fit_tracks (TrackSelection & tracks)
                        first_y_pos = std::min ((*t)->y_position (), first_y_pos);
                } else {
                        if (prev_was_selected && next_is_selected) {
-                               hide_track_in_display (**t);
+                               hide_track_in_display (*t);
                        }
                }
 
@@ -6490,7 +6748,7 @@ void
 Editor::start_visual_state_op (uint32_t 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);
+               visual_state_op_connection = Glib::signal_timeout().connect (sigc::bind (sigc::mem_fun (*this, &Editor::end_visual_state_op), n), 1000);
        }
 }