don't go through ::deliver_enter_leave() unnecessarily

diff --git a/libs/canvas/canvas.cc b/libs/canvas/canvas.cc
index db38d2d9a1cc0dbf0efd544b3bb95128064b54f6..5e5fd6e7277ef7fc506976fb00af80bada7c6416 100644 (file)
--- a/libs/canvas/canvas.cc
+++ b/libs/canvas/canvas.cc
@@ -338,6 +338,7 @@ GtkCanvas::pick_current_item (Duple const & point, int state)
                /* no items at point, just send leave event below */
 
        } else {
+
                if (within_items.front() == _current_item) {
                        /* uppermost item at point is already _current_item */
                        return;
@@ -346,7 +347,9 @@ GtkCanvas::pick_current_item (Duple const & point, int state)
                _new_current_item = const_cast<Item*> (within_items.front());
        }
 
-       deliver_enter_leave (point, state);
+       if (_new_current_item != _current_item) {
+               deliver_enter_leave (point, state);
+       }
 }
 
 void
@@ -404,7 +407,7 @@ GtkCanvas::deliver_enter_leave (Duple const & point, int state)
        } else if (_current_item->is_descendant_of (*_new_current_item)) {
 
                /* move from descendant to ancestor (X: "_current_item is an
-                * inferior of _new_current_item") 
+                * inferior ("child") of _new_current_item") 
                 *
                 * Deliver "virtual" leave notifications to all items in the
                 * heirarchy between current and new_current.
@@ -421,7 +424,7 @@ GtkCanvas::deliver_enter_leave (Duple const & point, int state)
 
        } else if (_new_current_item->is_descendant_of (*_current_item)) {
                /* move from ancestor to descendant (X: "_new_current_item is
-                * an inferior of _current_item")
+                * an inferior ("child") of _current_item")
                 *
                 * Deliver "virtual" enter notifications to all items in the
                 * heirarchy between current and new_current.