patches from lincoln to speed up the regionlist and provide region removal (causes dangling shared ptrs to regions, fix to come

git-svn-id: svn://localhost/ardour2/branches/3.0@8845 d708f5d6-7413-0410-9779-e7cbd77b26cf

16 files changed, 458 insertions, 352 deletions

diff --git a/gtk2_ardour/ardour.menus.in b/gtk2_ardour/ardour.menus.in
index 88a07fcaac..476af838b0 100644
--- a/gtk2_ardour/ardour.menus.in
+++ b/gtk2_ardour/ardour.menus.in
@@ -540,7 +540,7 @@
          <menuitem action='rlAudition'/>
          <menuitem action='rlHide'/>
          <menuitem action='rlShow'/>
-	  <separator/>
+	 <separator/>
          <menuitem action='rlShowAll'/>
          <menuitem action='rlShowAuto'/>
          <menu name='Sort' action='RegionListSort'>
@@ -559,7 +559,9 @@
                <menuitem action='SortBySourceFilesystem'/>
          </menu>
          <separator/>
-         <menuitem action='addExternalAudioToRegionList'/>	       
+         <menuitem action='addExternalAudioToRegionList'/>
+         <separator/>
+         <menuitem action='removeUnusedRegions'/>    
      </popup>
 
 	<popup name='PopupRegionMenu' action='PopupRegionMenu'>
diff --git a/gtk2_ardour/audio_region_view.cc b/gtk2_ardour/audio_region_view.cc
index b72d95ca15..4a5a477a5c 100644
--- a/gtk2_ardour/audio_region_view.cc
+++ b/gtk2_ardour/audio_region_view.cc
@@ -269,10 +269,10 @@ AudioRegionView::~AudioRegionView ()
 		delete *i;
 	}
 
-	for (list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator i = feature_lines.begin(); i != feature_lines.end(); ++i) {
+	for (list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator i = feature_lines.begin(); i != feature_lines.end(); ++i) {
 		delete ((*i).second);
 	}
-	
+
 	/* all waveviews etc will be destroyed when the group is destroyed */
 
 	delete gain_line;
@@ -407,8 +407,8 @@ AudioRegionView::region_resized (const PropertyChange& what_changed)
 		}
 		
 		/* hide transient lines that extend beyond the region end */
-		
-		list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
+
+		list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
 		
 		for (l = feature_lines.begin(); l != feature_lines.end(); ++l) {
 			if ((*l).first > _region->length()- 1){
@@ -444,11 +444,19 @@ AudioRegionView::reset_width_dependent_items (double pixel_width)
 
 	AnalysisFeatureList analysis_features = _region->transients();
 	AnalysisFeatureList::const_iterator i;
-	list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
+
+	list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
 
 	for (i = analysis_features.begin(), l = feature_lines.begin(); i != analysis_features.end() && l != feature_lines.end(); ++i, ++l) {
-		(*l).second->property_x1() = trackview.editor().frame_to_pixel (*i);
-		(*l).second->property_x2() = trackview.editor().frame_to_pixel (*i);
+	  
+		float x_pos = trackview.editor().frame_to_pixel (*i);
+		
+		ArdourCanvas::Points points;
+		points.push_back(Gnome::Art::Point(x_pos, 2.0)); // first x-coord needs to be a non-normal value
+		points.push_back(Gnome::Art::Point(x_pos, _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1));
+
+		(*l).first = *i;
+		(*l).second->property_points() = points;
 	}
 	
 	reset_fade_shapes ();
@@ -526,13 +534,22 @@ AudioRegionView::set_height (gdouble height)
 	reset_fade_shapes ();
 	
 	/* Update hights for any active feature lines */
-	list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
-
+	list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
+	
 	for (l = feature_lines.begin(); l != feature_lines.end(); ++l) {
-		(*l).second->property_y2() = _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1;
-	}	
+
+		float pos_x = trackview.editor().frame_to_pixel((*l).first);
+
+		ArdourCanvas::Points points;
+		
+		points.push_back(Gnome::Art::Point(pos_x, 2.0)); // first x-coord needs to be a non-normal value
+		points.push_back(Gnome::Art::Point(pos_x, _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1));
+
+		(*l).second->property_points() = points;
+	}
 
 	if (fade_position_line) {
+
 		if (height < NAME_HIGHLIGHT_THRESH) {
 			fade_position_line->property_y2() = _height - 1;
 		}
@@ -1430,31 +1447,55 @@ AudioRegionView::transients_changed ()
 	AnalysisFeatureList analysis_features = _region->transients();
 
 	while (feature_lines.size() < analysis_features.size()) {
-		ArdourCanvas::SimpleLine* l = new ArdourCanvas::SimpleLine (*group);
-		l->property_color_rgba() = (guint) ARDOUR_UI::config()->canvasvar_ZeroLine.get();
-		feature_lines.push_back (make_pair(0, l));
+
+		ArdourCanvas::Line* canvas_item = new ArdourCanvas::Line(*group);
+	
+		ArdourCanvas::Points points;
+		
+		points.push_back(Gnome::Art::Point(-1.0, 2.0)); // first x-coord needs to be a non-normal value
+		points.push_back(Gnome::Art::Point(1.0, _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1));
+
+		canvas_item->property_points() = points;
+		canvas_item->property_width_pixels() = 1;
+		canvas_item->property_fill_color_rgba() = ARDOUR_UI::config()->canvasvar_ZeroLine.get();
+		canvas_item->property_first_arrowhead() = TRUE;
+		canvas_item->property_last_arrowhead() = TRUE;
+		canvas_item->property_arrow_shape_a() = 11.0;
+		canvas_item->property_arrow_shape_b() = 0.0;
+		canvas_item->property_arrow_shape_c() = 4.0;
+
+		canvas_item->raise_to_top ();
+		canvas_item->show ();
+		
+		canvas_item->set_data ("regionview", this);
+		canvas_item->signal_event().connect (sigc::bind (sigc::mem_fun (PublicEditor::instance(), &PublicEditor::canvas_feature_line_event), canvas_item, this));
+		
+		feature_lines.push_back (make_pair(0, canvas_item));		
 	}
 
 	while (feature_lines.size() > analysis_features.size()) {
-		ArdourCanvas::SimpleLine *line = feature_lines.back().second;
+		ArdourCanvas::Line* line = feature_lines.back().second;
 		feature_lines.pop_back ();
 		delete line;
 	}
 
 	AnalysisFeatureList::const_iterator i;
-	list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
-
+	list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
+	
 	for (i = analysis_features.begin(), l = feature_lines.begin(); i != analysis_features.end() && l != feature_lines.end(); ++i, ++l) {
-		(*l).first = *i;
-		(*l).second->property_x1() = trackview.editor().frame_to_pixel (*i);
-		(*l).second->property_x2() = trackview.editor().frame_to_pixel (*i);		
-		(*l).second->property_y1() = 2;
-		(*l).second->property_y2() = _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1;
-		(*l).second->set_data("regionview", this);
-		(*l).second->show ();
-		(*l).second->raise_to_top ();
+
+		ArdourCanvas::Points points;
+
+		float *pos = new float;
+		*pos = trackview.editor().frame_to_pixel (*i);
 		
-		(*l).second->signal_event().connect (sigc::bind (sigc::mem_fun (PublicEditor::instance(), &PublicEditor::canvas_feature_line_event), (*l).second, this));
+		points.push_back(Gnome::Art::Point(*pos, 2.0)); // first x-coord needs to be a non-normal value
+		points.push_back(Gnome::Art::Point(*pos, _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1));
+
+		(*l).second->property_points() = points;
+		(*l).second->set_data ("position", pos);
+		
+		(*l).first = *i;
 	}
 }
 
@@ -1462,12 +1503,16 @@ void
 AudioRegionView::update_transient(float /*old_pos*/, float new_pos)
 {
 	/* Find frame at old pos, calulate new frame then update region transients*/
-	list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
+	list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
 
 	for (l = feature_lines.begin(); l != feature_lines.end(); ++l) {
-		/* Simple line x1 has been updated in drag so we compare to new_pos */
-		if (rint(new_pos) == rint((*l).second->property_x1())) {
-		    
+
+		/* Line has been updated in drag so we compare to new_pos */
+		
+		float* pos = (float*) (*l).second->get_data ("position");
+		
+		if (rint(new_pos) == rint(*pos)) { 
+		  
 		    framepos_t old_frame = (*l).first;
 		    framepos_t new_frame = trackview.editor().pixel_to_frame (new_pos);
 
@@ -1482,12 +1527,15 @@ void
 AudioRegionView::remove_transient(float pos)
 {
 	/* Find frame at old pos, calulate new frame then update region transients*/
-	list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> >::iterator l;
+	list<std::pair<framepos_t, ArdourCanvas::Line*> >::iterator l;
 
 	for (l = feature_lines.begin(); l != feature_lines.end(); ++l) {
-		/* Simple line x1 has been updated in drag so we compare to new_pos */
-		if (rint(pos) == rint((*l).second->property_x1())) {
-		    _region->remove_transient ((*l).first);		    
+
+		/* Line has been updated in drag so we compare to new_pos */
+		float *line_pos = (float*) (*l).second->get_data ("position");
+
+		if (rint(pos) == rint(*line_pos)) {
+		    _region->remove_transient ((*l).first);   
 		    break;
 		}
 	}
diff --git a/gtk2_ardour/audio_region_view.h b/gtk2_ardour/audio_region_view.h
index f7b8404d7b..a2ec896a16 100644
--- a/gtk2_ardour/audio_region_view.h
+++ b/gtk2_ardour/audio_region_view.h
@@ -135,9 +135,9 @@ class AudioRegionView : public RegionView
 	
 	std::vector<ArdourCanvas::WaveView *> waves;
 	std::vector<ArdourCanvas::WaveView *> tmp_waves; ///< see ::create_waves()
+
+	std::list<std::pair<framepos_t, ArdourCanvas::Line*> > feature_lines;
 	
-	std::list<std::pair<framepos_t, ArdourCanvas::SimpleLine*> > feature_lines;
-    
 	ArdourCanvas::Polygon*           sync_mark; ///< polgyon for sync position
 	ArdourCanvas::SimpleLine*        zero_line;
 	ArdourCanvas::Polygon*           fade_in_shape;
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 256c8e296c..6903cd20c9 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -1385,6 +1385,9 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	bool canvas_markerview_item_view_event(GdkEvent* event, ArdourCanvas::Item*,MarkerView*);
 	bool canvas_markerview_start_handle_event(GdkEvent* event, ArdourCanvas::Item*,MarkerView*);
 	bool canvas_markerview_end_handle_event(GdkEvent* event, ArdourCanvas::Item*,MarkerView*);
+	
+	PBD::Signal0<void> EditorFreeze;
+	PBD::Signal0<void> EditorThaw;
 
   private:
         friend class DragManager;
diff --git a/gtk2_ardour/editor_actions.cc b/gtk2_ardour/editor_actions.cc
index 6f1579bb5a..c3a62cb63f 100644
--- a/gtk2_ardour/editor_actions.cc
+++ b/gtk2_ardour/editor_actions.cc
@@ -631,13 +631,16 @@ Editor::register_actions ()
 
 	act = ActionManager::register_action (rl_actions, X_("rlAudition"), _("Audition"), sigc::mem_fun(*this, &Editor::audition_region_from_region_list));
 	ActionManager::region_list_selection_sensitive_actions.push_back (act);
+	
 	act = ActionManager::register_action (rl_actions, X_("rlHide"), _("Hide"), sigc::mem_fun(*this, &Editor::hide_region_from_region_list));
 	ActionManager::region_list_selection_sensitive_actions.push_back (act);
+	
 	act = ActionManager::register_action (rl_actions, X_("rlShow"), _("Show"), sigc::mem_fun(*this, &Editor::show_region_in_region_list));
 	ActionManager::region_list_selection_sensitive_actions.push_back (act);
+	
 	ActionManager::register_toggle_action (rl_actions, X_("rlShowAll"), _("Show All"), sigc::mem_fun(*_regions, &EditorRegions::toggle_full));
 	ActionManager::register_toggle_action (rl_actions, X_("rlShowAuto"), _("Show Automatic Regions"), sigc::mem_fun (*_regions, &EditorRegions::toggle_show_auto_regions));
-
+	
 	ActionManager::register_radio_action (rl_actions, sort_order_group, X_("SortAscending"),  _("Ascending"),
 			sigc::bind (sigc::mem_fun (*_regions, &EditorRegions::reset_sort_direction), true));
 	ActionManager::register_radio_action (rl_actions, sort_order_group, X_("SortDescending"),   _("Descending"),
@@ -664,6 +667,7 @@ Editor::register_actions ()
 	ActionManager::register_radio_action (rl_actions, sort_type_group, X_("SortBySourceFilesystem"),  _("By Source Filesystem"),
 			sigc::bind (sigc::mem_fun (*_regions, &EditorRegions::reset_sort_type), BySourceFileFS, false));
 
+	ActionManager::register_action (rl_actions, X_("removeUnusedRegions"), _("Delete Unused"), sigc::mem_fun(*_regions, &EditorRegions::delete_unused_regions));
 
 	/* the next two are duplicate items with different names for use in two different contexts */
 
@@ -747,6 +751,7 @@ Editor::toggle_ruler_visibility (RulerType rt)
 	}
 
 	Glib::RefPtr<Action> act = ActionManager::get_action (X_("Rulers"), action);
+	
 	if (act) {
 		Glib::RefPtr<ToggleAction> tact = Glib::RefPtr<ToggleAction>::cast_dynamic(act);
 		update_ruler_visibility ();
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index b06545c32b..f0e53ab584 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -2900,7 +2900,7 @@ FeatureLineDrag::start_grab (GdkEvent* event, Gdk::Cursor* /*cursor*/)
 {
 	Drag::start_grab (event);
 	
-	_line = reinterpret_cast<SimpleLine*> (_item);
+	_line = reinterpret_cast<Line*> (_item);
 	assert (_line);
 
 	/* need to get x coordinate in terms of parent (AudioRegionView) origin. */
@@ -2913,10 +2913,10 @@ FeatureLineDrag::start_grab (GdkEvent* event, Gdk::Cursor* /*cursor*/)
 	/* store grab start in parent frame */
 	_region_view_grab_x = cx;
 	
-	_before = _line->property_x1();
+	_before = *(float*) _item->get_data ("position");
 	
 	_arv = reinterpret_cast<AudioRegionView*> (_item->get_data ("regionview"));
-		
+
 	_max_x = _editor->frame_to_pixel(_arv->get_duration());
 }
 
@@ -2938,17 +2938,30 @@ FeatureLineDrag::motion (GdkEvent*, bool)
 		cx = 0;
 	}
 	
-	_line->property_x1() = cx; 
-	_line->property_x2() = cx;
+	ArdourCanvas::Points points;
+	
+	double x1 = 0, x2 = 0, y1 = 0, y2 = 0;
+
+	_line->get_bounds(x1, y2, x2, y2);
+	
+	points.push_back(Gnome::Art::Point(cx, 2.0)); // first x-coord needs to be a non-normal value
+	points.push_back(Gnome::Art::Point(cx, y2 - y1));
 
-	_before = _line->property_x1();
+	_line->property_points() = points;
+	
+	float *pos = new float;
+	*pos = cx;
+	
+	_line->set_data ("position", pos);
+
+	_before = cx;
 }
 
 void
 FeatureLineDrag::finished (GdkEvent*, bool)
 {
 	_arv = reinterpret_cast<AudioRegionView*> (_item->get_data ("regionview"));
-	_arv->update_transient(_before, _line->property_x1());
+	_arv->update_transient(_before, _before);
 }
 
 void
@@ -3049,6 +3062,7 @@ RubberbandSelectDrag::finished (GdkEvent* event, bool movement_occurred)
 		}
 
 		_editor->commit_reversible_command ();
+
 	} else {
 		if (!getenv("ARDOUR_SAE")) {
 			_editor->selection->clear_tracks();
diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index ab81db5a63..ce8a1370f4 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -731,13 +731,13 @@ public:
 
 private:
 
-	ArdourCanvas::SimpleLine* _line;
+	ArdourCanvas::Line* _line;
 	AudioRegionView* _arv;
 	
 	double _region_view_grab_x;
 	double _cumulative_x_drag;
 	
-	uint32_t _before;
+	float _before;
 	uint32_t _max_x;
 };
 
diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index 2769a80570..6e5f8071b0 100644
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -1462,7 +1462,7 @@ Editor::button_release_handler (ArdourCanvas::Item* item, GdkEvent* event, ItemT
 			break;
 
 		case MouseAudition:
-                        set_canvas_cursor (current_canvas_cursor);
+			set_canvas_cursor (current_canvas_cursor);
 			if (scrubbing_direction == 0) {
 				/* no drag, just a click */
 				switch (item_type) {
@@ -1714,8 +1714,8 @@ Editor::enter_handler (ArdourCanvas::Item* item, GdkEvent* event, ItemType item_
 		break;
 	case FeatureLineItem:
 		{
-			ArdourCanvas::SimpleLine *line = dynamic_cast<ArdourCanvas::SimpleLine *> (item);
-			line->property_color_rgba() = 0xFF0000FF;
+			ArdourCanvas::Line *line = dynamic_cast<ArdourCanvas::Line *> (item);
+			line->property_fill_color_rgba() = 0xFF0000FF;
 		}
 		break;
 	case SelectionItem:
@@ -1874,8 +1874,8 @@ Editor::leave_handler (ArdourCanvas::Item* item, GdkEvent* event, ItemType item_
 		break;
 	case FeatureLineItem:
 		{
-			ArdourCanvas::SimpleLine *line = dynamic_cast<ArdourCanvas::SimpleLine *> (item);
-			line->property_color_rgba() = (guint) ARDOUR_UI::config()->canvasvar_ZeroLine.get();;
+			ArdourCanvas::Line *line = dynamic_cast<ArdourCanvas::Line *> (item);
+			line->property_fill_color_rgba() = (guint) ARDOUR_UI::config()->canvasvar_ZeroLine.get();;
 		}
 		break;
 
@@ -2477,7 +2477,7 @@ Editor::mouse_brush_insert_region (RegionView* rv, framepos_t pos)
 	double speed = rtv->track()->speed();
 
 	playlist->clear_changes ();
-	boost::shared_ptr<Region> new_region (RegionFactory::create (rv->region()));
+	boost::shared_ptr<Region> new_region (RegionFactory::create (rv->region(), true));
 	playlist->add_region (new_region, (framepos_t) (pos * speed));
 	_session->add_command (new StatefulDiffCommand (playlist));
 
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index d15180fd42..ede62d8d9b 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -120,6 +120,8 @@ Editor::redo (uint32_t n)
 void
 Editor::split_regions_at (framepos_t where, RegionSelection& regions)
 {
+	bool frozen = false;
+
 	list <boost::shared_ptr<Playlist > > used_playlists;
 
 	if (regions.empty()) {
@@ -142,6 +144,9 @@ Editor::split_regions_at (framepos_t where, RegionSelection& regions)
 		}
 	} else {
 		snap_to (where);
+		
+		frozen = true;
+		EditorFreeze(); /* Emit Signal */
 	}
 
 	for (RegionSelection::iterator a = regions.begin(); a != regions.end(); ) {
@@ -191,6 +196,10 @@ Editor::split_regions_at (framepos_t where, RegionSelection& regions)
 	}
 
 	commit_reversible_command ();
+	
+	if (frozen){
+		EditorThaw(); /* Emit Signal */
+	}
 }
 
 boost::shared_ptr<Region>
@@ -5851,8 +5860,9 @@ Editor::split_region_at_points (boost::shared_ptr<Region> r, AnalysisFeatureList
 		plist.add (ARDOUR::Properties::layer, 0);
 
 		boost::shared_ptr<Region> nr = RegionFactory::create (r->sources(), plist, false);
+
 		pl->add_region (nr, r->position() + pos);
-		
+
 		if (select_new) {
 			new_regions.push_front(nr);
 		}
@@ -5924,16 +5934,18 @@ Editor::remove_transient(ArdourCanvas::Item* item)
 		return;
 	}
 
-	ArdourCanvas::SimpleLine* _line = reinterpret_cast<ArdourCanvas::SimpleLine*> (item);
+	ArdourCanvas::Line* _line = reinterpret_cast<ArdourCanvas::Line*> (item);
 	assert (_line);
 
 	AudioRegionView* _arv = reinterpret_cast<AudioRegionView*> (item->get_data ("regionview"));
-	_arv->remove_transient(_line->property_x1());
+	_arv->remove_transient (*(float*) _line->get_data ("position"));
 }
 
 void
 Editor::snap_regions_to_grid ()
 {
+	list <boost::shared_ptr<Playlist > > used_playlists;
+	
 	RegionSelection rs = get_regions_from_selection_and_entered ();
 
 	if (!_session || rs.empty()) {
@@ -5943,17 +5955,36 @@ Editor::snap_regions_to_grid ()
 	_session->begin_reversible_command (_("snap regions to grid"));
 	
 	for (RegionSelection::iterator r = rs.begin(); r != rs.end(); ++r) {
+	  
+		boost::shared_ptr<Playlist> pl = (*r)->region()->playlist();
+	  
+		if (!pl->frozen()) {
+			/* we haven't seen this playlist before */
+
+			/* remember used playlists so we can thaw them later */
+			used_playlists.push_back(pl);
+			pl->freeze();
+		}
+
 		framepos_t start_frame = (*r)->region()->first_frame ();
 		snap_to (start_frame);
 		(*r)->region()->set_position (start_frame, this);
 	}
 	
+	while (used_playlists.size() > 0) {
+		list <boost::shared_ptr<Playlist > >::iterator i = used_playlists.begin();
+		(*i)->thaw();
+		used_playlists.pop_front();
+	}
+
 	_session->commit_reversible_command ();
 }
 
 void
 Editor::close_region_gaps ()
-{	
+{
+	list <boost::shared_ptr<Playlist > > used_playlists;
+	
 	RegionSelection rs = get_regions_from_selection_and_entered ();
 
 	if (!_session || rs.empty()) {
@@ -6007,13 +6038,23 @@ Editor::close_region_gaps ()
 	/* 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) {
+	  
+		boost::shared_ptr<Playlist> pl = (*r)->region()->playlist();
+		
+		if (!pl->frozen()) {
+			/* we haven't seen this playlist before */
+
+			/* remember used playlists so we can thaw them later */
+			used_playlists.push_back(pl);
+			pl->freeze();
+		}
 
 		framepos_t position = (*r)->region()->position();
 	  
@@ -6031,6 +6072,12 @@ Editor::close_region_gaps ()
 		idx++;
 	}
 	
+	while (used_playlists.size() > 0) {
+		list <boost::shared_ptr<Playlist > >::iterator i = used_playlists.begin();
+		(*i)->thaw();
+		used_playlists.pop_front();
+	}
+
 	_session->commit_reversible_command ();
 }
 
diff --git a/gtk2_ardour/editor_regions.cc b/gtk2_ardour/editor_regions.cc
index 357bb7295e..e4798650b1 100644
--- a/gtk2_ardour/editor_regions.cc
+++ b/gtk2_ardour/editor_regions.cc
@@ -34,6 +34,7 @@
 #include "ardour/silentfilesource.h"
 #include "ardour/profile.h"
 
+#include "gtkmm2ext/choice.h"
 #include "gtkmm2ext/treeutils.h"
 
 #include "editor.h"
@@ -72,6 +73,7 @@ EditorRegions::EditorRegions (Editor* e)
 	_display.set_size_request (100, -1);
 	_display.set_name ("RegionListDisplay");
 	_display.set_rules_hint (true);
+	
 	/* Try to prevent single mouse presses from initiating edits.
 	   This relies on a hack in gtktreeview.c:gtk_treeview_button_press()
 	*/
@@ -117,24 +119,28 @@ EditorRegions::EditorRegions (Editor* e)
 	CellRendererToggle* locked_cell = dynamic_cast<CellRendererToggle*> (_display.get_column_cell_renderer (7));
 	locked_cell->property_activatable() = true;
 	locked_cell->signal_toggled().connect (sigc::mem_fun (*this, &EditorRegions::locked_changed));
+	
 	TreeViewColumn* locked_col = _display.get_column (7);
 	locked_col->add_attribute (locked_cell->property_visible(), _columns.property_toggles_visible);
 
 	CellRendererToggle* glued_cell = dynamic_cast<CellRendererToggle*> (_display.get_column_cell_renderer (8));
 	glued_cell->property_activatable() = true;
 	glued_cell->signal_toggled().connect (sigc::mem_fun (*this, &EditorRegions::glued_changed));
+	
 	TreeViewColumn* glued_col = _display.get_column (8);
 	glued_col->add_attribute (glued_cell->property_visible(), _columns.property_toggles_visible);
 
 	CellRendererToggle* muted_cell = dynamic_cast<CellRendererToggle*> (_display.get_column_cell_renderer (9));
 	muted_cell->property_activatable() = true;
 	muted_cell->signal_toggled().connect (sigc::mem_fun (*this, &EditorRegions::muted_changed));
+	
 	TreeViewColumn* muted_col = _display.get_column (9);
 	muted_col->add_attribute (muted_cell->property_visible(), _columns.property_toggles_visible);
 
 	CellRendererToggle* opaque_cell = dynamic_cast<CellRendererToggle*> (_display.get_column_cell_renderer (10));
 	opaque_cell->property_activatable() = true;
 	opaque_cell->signal_toggled().connect (sigc::mem_fun (*this, &EditorRegions::opaque_changed));
+	
 	TreeViewColumn* opaque_col = _display.get_column (10);
 	opaque_col->add_attribute (opaque_cell->property_visible(), _columns.property_toggles_visible);
 	
@@ -171,6 +177,9 @@ EditorRegions::EditorRegions (Editor* e)
 	ARDOUR_UI::instance()->secondary_clock.mode_changed.connect (sigc::mem_fun(*this, &EditorRegions::update_all_rows));
 	ARDOUR::Region::RegionPropertyChanged.connect (region_property_connection, MISSING_INVALIDATOR, ui_bind (&EditorRegions::region_changed, this, _1, _2), gui_context());
 	ARDOUR::RegionFactory::CheckNewRegion.connect (check_new_region_connection, MISSING_INVALIDATOR, ui_bind (&EditorRegions::add_region, this, _1), gui_context());
+	
+	e->EditorFreeze.connect (editor_freeze_connection, MISSING_INVALIDATOR, ui_bind (&EditorRegions::freeze_tree_model, this), gui_context());
+	e->EditorThaw.connect (editor_thaw_connection, MISSING_INVALIDATOR, ui_bind (&EditorRegions::thaw_tree_model, this), gui_context());
 }
 
 bool
@@ -238,14 +247,6 @@ EditorRegions::set_session (ARDOUR::Session* s)
 }
 
 void
-EditorRegions::add_regions (vector<boost::shared_ptr<Region> >& regions)
-{
-	for (vector<boost::shared_ptr<Region> >::iterator x = regions.begin(); x != regions.end(); ++x) {
-		add_region (*x);
-	}
-}
-
-void
 EditorRegions::add_region (boost::shared_ptr<Region> region)
 {
 	if (!region || !_session) {
@@ -262,6 +263,7 @@ EditorRegions::add_region (boost::shared_ptr<Region> region)
 	}
 
 	if (region->hidden()) {
+
 		TreeModel::iterator iter = _model->get_iter ("0");
 		TreeModel::Row parent;
 		TreeModel::Row child;
@@ -282,6 +284,7 @@ EditorRegions::add_region (boost::shared_ptr<Region> region)
 				parent = *iter;
 			}
 		}
+
 		row = *(_model->append (parent.children()));
 
 	} else if (region->whole_file()) {
@@ -357,31 +360,29 @@ EditorRegions::add_region (boost::shared_ptr<Region> region)
 			}
 		}
 
-		if (region->automatic()) {
-			return;
-		}
-
-	} else {
+		region_row_map.insert(pair<boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::RowReference>(region, TreeRowReference(_model, TreePath (row))) );
+		parent_regions_sources_map.insert(pair<string, Gtk::TreeModel::RowReference>(region->source_string(), TreeRowReference(_model, TreePath (row))) );
 
-		/* find parent node, add as new child */
+		return;
 
+	} else {
+		// find parent node, add as new child
 		TreeModel::iterator i;
 		TreeModel::Children rows = _model->children();
-		bool found_parent = false;
-
-		for (i = rows.begin(); i != rows.end(); ++i) {
-			boost::shared_ptr<Region> r = (*i)[_columns.region];
-
-			if (r && r->whole_file()) {
-
-				if (region->source_equivalent (r)) {
-					found_parent = true;
-				}
-			}
                         
+		boost::unordered_map<string, Gtk::TreeModel::RowReference>::iterator it;
+		
+		it = parent_regions_sources_map.find (region->source_string());
+		
+		if (it != parent_regions_sources_map.end()){
+
+			TreeModel::iterator j = _model->get_iter ((*it).second.get_path());
+		
 			TreeModel::iterator ii;
-			TreeModel::Children subrows = (*i).children();
+			TreeModel::Children subrows = (*j).children();
 
+			/* XXXX: should we be accounting for all regions? */
+			/*
 			for (ii = subrows.begin(); ii != subrows.end(); ++ii) {
 				boost::shared_ptr<Region> rr = (*ii)[_columns.region];
 
@@ -389,15 +390,12 @@ EditorRegions::add_region (boost::shared_ptr<Region> region)
 					return;
 				}
 			}
-
-			if (found_parent) {
-				row = *(_model->append ((*i).children()));
-				break;
-			}
+			*/
+			
+			row = *(_model->insert (subrows.end()));
 		}
-
-		if (!found_parent) {
-			row = *(_model->append());
+		else {
+		  row = *(_model->append());
 		}
 
 		row[_columns.property_toggles_visible] = true;
@@ -405,10 +403,38 @@ EditorRegions::add_region (boost::shared_ptr<Region> region)
 
 	row[_columns.region] = region;
 
+	region_row_map.insert(pair<boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::RowReference>(region, TreeRowReference(_model, TreePath (row))) );
+
 	populate_row(region, (*row));
 }
 
 void
+EditorRegions::delete_unused_regions ()
+{
+	vector<string> choices;
+	string prompt;
+
+	if (!_session) {
+		return;
+	}
+
+	prompt  = _("Do you really want to remove unused regions?"
+		    "\n(This is destructive and cannot be undone)");
+
+	choices.push_back (_("No, do nothing."));
+	choices.push_back (_("Yes, remove."));
+
+	Gtkmm2ext::Choice prompter (_("Remove unused regions"), prompt, choices);
+
+	if (prompter.run () == 1) {
+		_no_redisplay = true;
+		_session->cleanup_regions ();
+		_no_redisplay = false;
+		redisplay ();
+	}
+}
+
+void
 EditorRegions::region_changed (boost::shared_ptr<Region> r, const PropertyChange& what_changed)
 {
 	PropertyChange our_interests;
@@ -424,101 +450,48 @@ EditorRegions::region_changed (boost::shared_ptr<Region> r, const PropertyChange
 	our_interests.add (ARDOUR::Properties::fade_in);
 	our_interests.add (ARDOUR::Properties::fade_out);
 	
-	if (last_row != 0) {
-
-		TreeModel::iterator j = _model->get_iter (last_row.get_path());
-		boost::shared_ptr<Region> c = (*j)[_columns.region];
-
-		if (c == r) {
-			populate_row (r, (*j));
-			
-			if (what_changed.contains (ARDOUR::Properties::hidden)) {
-				redisplay ();
-			}
-			
-			return;
-		}
-	}
-
 	if (what_changed.contains (our_interests)) {
 
-		/* find the region in our model and update its row */
-		TreeModel::Children rows = _model->children ();
-		TreeModel::iterator i = rows.begin ();
-		
-		while (i != rows.end ()) {
+		if (last_row != 0) {
 
-			TreeModel::Children children = (*i)->children ();
-			TreeModel::iterator found = children.end ();
-			
-			boost::shared_ptr<Region> c = (*i)[_columns.region];
+			TreeModel::iterator j = _model->get_iter (last_row.get_path());
+			boost::shared_ptr<Region> c = (*j)[_columns.region];
 
 			if (c == r) {
-
-				/* check this row */
-				last_row = TreeRowReference (_model, TreePath (i));
-				found = i;
-
-			} else {
-
-				/* check its children */
+				populate_row (r, (*j));
 				
-				found = children.begin ();
-				while (found != children.end()) {
-			  
-					boost::shared_ptr<Region> c = (*found)[_columns.region];
-					
-					if (c == r) {
-						last_row = TreeRowReference(_model, TreePath (found));
-						break;
-					}
-					++found;
+				if (what_changed.contains (ARDOUR::Properties::hidden)) {
+					redisplay ();
 				}
+				
+				return;
 			}
+		}
+		
+		RegionRowMap::iterator it;
+		
+		it = region_row_map.find (r);
+		
+		if (it != region_row_map.end()){
 
-			if (found != children.end()) {
-
-				boost::shared_ptr<AudioRegion> audioregion = boost::dynamic_pointer_cast<AudioRegion>(r);
-				uint32_t used = _editor->get_regionview_count_from_region_list (r);
+			TreeModel::iterator j = _model->get_iter ((*it).second.get_path());
+			boost::shared_ptr<Region> c = (*j)[_columns.region];
 
-				if (what_changed.contains (ARDOUR::Properties::name)) {
-					populate_row_name (r, *found);
-				}
-				if (what_changed.contains (ARDOUR::Properties::position)) {
-					populate_row_position (r, *found, used);
-					populate_row_end (r, *found, used);
-				}
-				if (what_changed.contains (ARDOUR::Properties::length)) {
-					populate_row_end (r, *found, used);
-					populate_row_length (r, *found);
-				}
-				if (what_changed.contains (ARDOUR::Properties::start)) {
-					populate_row_length (r, *found);
-				}
-				if (what_changed.contains (ARDOUR::Properties::locked)) {
-					populate_row_locked (r, *found, used);
-				}
-				if (what_changed.contains (ARDOUR::Properties::position_lock_style)) {
-					populate_row_glued (r, *found, used);
-				}
-				if (what_changed.contains (ARDOUR::Properties::muted)) {
-					populate_row_muted (r, *found, used);
-				}
-				if (what_changed.contains (ARDOUR::Properties::opaque)) {
-					populate_row_opaque (r, *found, used);
-				}
-				if (what_changed.contains (ARDOUR::Properties::fade_in)) {
-					populate_row_fade_in (r, *found, used, audioregion);
-				}
-				if (what_changed.contains (ARDOUR::Properties::fade_out)) {
-					populate_row_fade_out (r, *found, used, audioregion);
+			if (c == r) {
+				populate_row (r, (*j));
+				
+				if (what_changed.contains (ARDOUR::Properties::hidden)) {
+					redisplay ();
 				}
+				
+				return;
+			}    
+		}
 
-				break;
-			}
+		/* find the region in our model and update its row */
+		TreeModel::Children rows = _model->children ();
+		TreeModel::iterator i = rows.begin ();
 
-			++i;
-		}
 	}
 
 	if (what_changed.contains (ARDOUR::Properties::hidden)) {
@@ -576,67 +549,19 @@ EditorRegions::selection_changed ()
 void
 EditorRegions::set_selected (RegionSelection& regions)
 {
-	TreeModel::Children rows = _model->children();
-
-	for (RegionSelection::iterator iter = regions.begin(); iter != regions.end(); ++iter) {
+	for (RegionSelection::iterator i = regions.begin(); i != regions.end(); ++i) {
 
-		TreeModel::iterator i;
+		boost::shared_ptr<Region> r ((*i)->region());
 		
-		boost::shared_ptr<Region> r ((*iter)->region());
-
-		for (i = rows.begin(); i != rows.end(); ++i) {
-
-			boost::shared_ptr<Region> compared_region = (*i)[_columns.region];
-
-			if (r == compared_region) {
-				_display.get_selection()->select(*i);
-				break;
-			}
-
-			if (!(*i).children().empty()) {
-				if (set_selected_in_subrow(r, (*i), 2)) {
-					break;
-				}
-			}
-		}
-	}
-}
-
-bool
-EditorRegions::set_selected_in_subrow (boost::shared_ptr<Region> region, TreeModel::Row const &parent_row, int level)
-{
-	TreeModel::iterator i;
-	TreeModel::Children subrows = (*parent_row).children();
-
-	for (i = subrows.begin(); i != subrows.end(); ++i) {
-
-		boost::shared_ptr<Region> compared_region = (*i)[_columns.region];
-
-		if (region == compared_region) {
-			_display.get_selection()->select(*i);
-			return true;
-		}
+		RegionRowMap::iterator it;
+		
+		it = region_row_map.find (r);
 
-		if (!(*i).children().empty()) {
-			if (set_selected_in_subrow (region, (*i), level + 1)) {
-				return true;
-			}
+		if (it != region_row_map.end()){
+			TreeModel::iterator j = _model->get_iter ((*it).second.get_path());
+			_display.get_selection()->select(*j);
 		}
 	}
-	
-	return false;
-}
-
-void
-EditorRegions::insert_into_tmp_regionlist(boost::shared_ptr<Region> region)
-{
-	/* keep all whole files at the beginning */
-
-	if (region->whole_file()) {
-		tmp_region_list.push_front (region);
-	} else {
-		tmp_region_list.push_back (region);
-	}
 }
 
 void
@@ -655,23 +580,36 @@ EditorRegions::redisplay ()
 
 	_display.set_model (Glib::RefPtr<Gtk::TreeStore>(0));
 	_model->clear ();
+	_model->set_sort_column (-2, SORT_ASCENDING); //Disable sorting to gain performance
+	
 
+	region_row_map.clear();
+	parent_regions_sources_map.clear();
+	
 	/* now add everything we have, via a temporary list used to help with sorting */
 
-	tmp_region_list.clear();
-
 	const RegionFactory::RegionMap& regions (RegionFactory::regions());
+
 	for (RegionFactory::RegionMap::const_iterator i = regions.begin(); i != regions.end(); ++i) {
-		insert_into_tmp_regionlist (i->second);
+		
+		if ( i->second->whole_file()) {
+			/* add automatic regions first so that children can find their parents as we add them */
+			add_region (i->second);
+			continue;
+		}
+
+		tmp_region_list.push_front (i->second);
 	}
 
 	for (list<boost::shared_ptr<Region> >::iterator r = tmp_region_list.begin(); r != tmp_region_list.end(); ++r) {
 		add_region (*r);
 	}
-	tmp_region_list.clear();
-
+	
+	_model->set_sort_column (0, SORT_ASCENDING); // renabale sorting
 	_display.set_model (_model);
 
+	tmp_region_list.clear();
+
 	if (tree_expanded) {
 		_display.expand_all();
 	}
@@ -684,59 +622,15 @@ EditorRegions::update_row (boost::shared_ptr<Region> region)
 		return;
 	}
 
-	TreeModel::iterator i;
-	TreeModel::Children rows = _model->children();
+	RegionRowMap::iterator it;
 	
-	return;
+	it = region_row_map.find (region);
 
-	for (i = rows.begin(); i != rows.end(); ++i) {
+	if (it != region_row_map.end()){
 
-//		cerr << "Level 1: Compare " << region->name() << " with parent " << (*i)[_columns.name] << "\n";
-
-		boost::shared_ptr<Region> compared_region = (*i)[_columns.region];
-
-		if (region == compared_region) {
-//			cerr << "Matched\n";
-			populate_row(region, (*i));
-			return;
-		}
-
-		if (!(*i).children().empty()) {
-			if (update_subrows(region, (*i), 2)) {
-				return;
-			}
-		}
+		TreeModel::iterator j = _model->get_iter ((*it).second.get_path());
+		populate_row(region, (*j));
 	}
-
-//	cerr << "Returning - No match\n";
-}
-
-bool
-EditorRegions::update_subrows (boost::shared_ptr<Region> region, TreeModel::Row const &parent_row, int level)
-{
-	TreeModel::iterator i;
-	TreeModel::Children subrows = (*parent_row).children();
-
-	for (i = subrows.begin(); i != subrows.end(); ++i) {
-
-//		cerr << "Level " << level << ": Compare " << region->name() << " with child " << (*i)[_columns.name] << "\n";
-
-		boost::shared_ptr<Region> compared_region = (*i)[_columns.region];
-
-		if (region == compared_region) {
-			populate_row(region, (*i));
-//			cerr << "Matched\n";
-			return true;
-		}
-
-		if (!(*i).children().empty()) {
-			if (update_subrows (region, (*i), level + 1)) {
-				return true;
-			}
-		}
-	}
-
-	return false;
 }
 
 void
@@ -745,40 +639,17 @@ EditorRegions::update_all_rows ()
 	if (!_session) {
 		return;
 	}
-	
-	TreeModel::iterator i;
-	TreeModel::Children rows = _model->children();
-
-	for (i = rows.begin(); i != rows.end(); ++i) {
-
-		boost::shared_ptr<Region> region = (*i)[_columns.region];
-
-		if (!region->automatic()) {
-			populate_row(region, (*i));
-		}
-
-		if (!(*i).children().empty()) {
-			update_all_subrows ((*i), 2);
-		}
-	}
-}
-
-void
-EditorRegions::update_all_subrows (TreeModel::Row const &parent_row, int level)
-{
-	TreeModel::iterator i;
-	TreeModel::Children subrows = (*parent_row).children();
 
-	for (i = subrows.begin(); i != subrows.end(); ++i) {
+	RegionRowMap::iterator i;
 
-		boost::shared_ptr<Region> region = (*i)[_columns.region];
+	for (i = region_row_map.begin(); i != region_row_map.end(); ++i) {
 
+		TreeModel::iterator j = _model->get_iter ((*i).second.get_path());
+		
+		boost::shared_ptr<Region> region = (*j)[_columns.region];
+		
 		if (!region->automatic()) {
-			populate_row(region, (*i));
-		}
-
-		if (!(*i).children().empty()) {
-			update_all_subrows ((*i), level + 1);
+			populate_row(region, (*j));
 		}
 	}
 }
@@ -827,8 +698,10 @@ void
 EditorRegions::populate_row (boost::shared_ptr<Region> region, TreeModel::Row const &row)
 {
 	boost::shared_ptr<AudioRegion> audioregion = boost::dynamic_pointer_cast<AudioRegion>(region);
-	uint32_t used = _session->playlists->region_use_count (region);
-
+	//uint32_t used = _session->playlists->region_use_count (region);
+	/* Presently a region is only used once so let's save on the sequential scan to determine use count */
+	uint32_t used = 1;
+	
 	populate_row_position (region, row, used);
 	populate_row_end (region, row, used);
 	populate_row_sync (region, row, used);
@@ -1448,6 +1321,25 @@ EditorRegions::get_single_selection ()
 	return (*iter)[_columns.region];
 }
 
+void 
+EditorRegions::freeze_tree_model (){
+ 
+	_display.set_model (Glib::RefPtr<Gtk::TreeStore>(0));
+	_model->set_sort_column (-2, SORT_ASCENDING); //Disable sorting to gain performance
+
+}
+
+void 
+EditorRegions::thaw_tree_model (){
+
+	_model->set_sort_column (0, SORT_ASCENDING); // renabale sorting
+	_display.set_model (_model);
+
+	if (toggle_full_action()->get_active()) {
+		_display.expand_all();
+	}
+}
+
 void
 EditorRegions::locked_changed (std::string const & path)
 {
@@ -1515,7 +1407,7 @@ EditorRegions::get_state () const
 
 	return *node;
 }
-		
+
 void
 EditorRegions::set_state (const XMLNode & node)
 {
@@ -1526,28 +1418,35 @@ EditorRegions::set_state (const XMLNode & node)
 	}
 
 	XMLProperty const * p = node.property (X_("sort-type"));
+	
 	if (p) {
 		Editing::RegionListSortType const t = static_cast<Editing::RegionListSortType> (string_2_enum (p->value(), _sort_type));
+
 		if (_sort_type != t) {
 			changed = true;
 		}
+
 		reset_sort_type (t, true);
 		RefPtr<RadioAction> ract = sort_type_action (t);
 		ract->set_active ();
 	}
 
 	p = node.property (X_("sort-ascending"));
+	
 	if (p) {
 		bool const yn = string_is_affirmative (p->value ());
 		SortType old_sort_type;
 		int old_sort_column;
 
 		_model->get_sort_column_id (old_sort_column, old_sort_type);
+		
 		if (old_sort_type != (yn ? SORT_ASCENDING : SORT_DESCENDING)) {
 			changed = true;
 		}
+
 		reset_sort_direction (yn);
 		RefPtr<Action> act;
+		
 		if (yn) {
 			act = ActionManager::get_action (X_("RegionList"), X_("SortAscending"));
 		} else {
@@ -1560,9 +1459,11 @@ EditorRegions::set_state (const XMLNode & node)
 	p = node.property (X_("show-all"));
 	if (p) {
 		bool const yn = string_is_affirmative (p->value ());
+
 		if (expanded != yn) {
 			changed = true;
 		}
+		
 		set_full (yn);
 		toggle_full_action()->set_active (yn);
 	}
@@ -1570,6 +1471,7 @@ EditorRegions::set_state (const XMLNode & node)
 	p = node.property (X_("show-automatic-regions"));
 	if (p) {
 		bool const yn = string_is_affirmative (p->value ());
+
 		if (yn != _show_automatic_regions) {
 			_show_automatic_regions = yn;
 			toggle_show_auto_regions_action()->set_active (yn);
@@ -1642,6 +1544,12 @@ EditorRegions::show_action () const
 	return ActionManager::get_action (X_("RegionList"), X_("rlShow"));
 }
 
+RefPtr<Action>
+EditorRegions::delete_unused_regions_action () const
+{
+	return ActionManager::get_action (X_("RegionList"), X_("removeUnusedRegions"));
+}
+
 RefPtr<ToggleAction>
 EditorRegions::toggle_full_action () const
 {
diff --git a/gtk2_ardour/editor_regions.h b/gtk2_ardour/editor_regions.h
index 0643befbdf..c9d2f8714e 100644
--- a/gtk2_ardour/editor_regions.h
+++ b/gtk2_ardour/editor_regions.h
@@ -20,6 +20,7 @@
 #define __gtk_ardour_editor_regions_h__
 
 #include "editor_component.h"
+#include <boost/unordered_map.hpp>
 
 class EditorRegions : public EditorComponent, public ARDOUR::SessionHandlePtr
 {
@@ -66,6 +67,8 @@ public:
 	void unselect_all () {
 		_display.get_selection()->unselect_all ();
 	}
+	
+	void delete_unused_regions();
 
 	XMLNode& get_state () const;
 	void set_state (const XMLNode &);
@@ -115,12 +118,13 @@ private:
 	
 	Gtk::TreeModel::RowReference last_row;
 
+	void freeze_tree_model ();
+	void thaw_tree_model ();
 	void region_changed (boost::shared_ptr<ARDOUR::Region>, PBD::PropertyChange const &);
 	void selection_changed ();
 	
 	sigc::connection _change_connection;
-	
-	bool set_selected_in_subrow (boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::Row const &, int);
+
 	bool selection_filter (const Glib::RefPtr<Gtk::TreeModel>& model, const Gtk::TreeModel::Path& path, bool yn);
 
         Gtk::Widget* old_focus;
@@ -135,10 +139,12 @@ private:
 
 	bool key_press (GdkEventKey *);
 	bool button_press (GdkEventButton *);
+
         bool focus_in (GdkEventFocus*);
         bool focus_out (GdkEventFocus*);
         bool enter_notify (GdkEventCrossing*);
         bool leave_notify (GdkEventCrossing*);
+
 	void show_context_menu (int button, int time);
 
 	int sorter (Gtk::TreeModel::iterator, Gtk::TreeModel::iterator);
@@ -146,7 +152,7 @@ private:
         void format_position (ARDOUR::framepos_t pos, char* buf, size_t bufsize);
 
 	void add_region (boost::shared_ptr<ARDOUR::Region>);
-	void add_regions (std::vector<boost::shared_ptr<ARDOUR::Region> > & );
+
 	void populate_row (boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::Row const &);
         void populate_row_used (boost::shared_ptr<ARDOUR::Region> region, Gtk::TreeModel::Row const& row, uint32_t used);
         void populate_row_position (boost::shared_ptr<ARDOUR::Region> region, Gtk::TreeModel::Row const& row, uint32_t used);
@@ -162,10 +168,9 @@ private:
         void populate_row_name (boost::shared_ptr<ARDOUR::Region> region, Gtk::TreeModel::Row const& row);
         void populate_row_source (boost::shared_ptr<ARDOUR::Region> region, Gtk::TreeModel::Row const& row);
 
-	void update_row (boost::shared_ptr<ARDOUR::Region>);
-	bool update_subrows (boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::Row const &, int);
+	void update_row (boost::shared_ptr<ARDOUR::Region>);	
 	void update_all_rows ();
-	void update_all_subrows (Gtk::TreeModel::Row const &, int);
+
 	void insert_into_tmp_regionlist (boost::shared_ptr<ARDOUR::Region>);
 
 	void drag_data_received (
@@ -177,22 +182,39 @@ private:
 
 	Glib::RefPtr<Gtk::Action> hide_action () const;
 	Glib::RefPtr<Gtk::Action> show_action () const;
+	Glib::RefPtr<Gtk::Action> delete_unused_regions_action() const;
 	Glib::RefPtr<Gtk::ToggleAction> toggle_full_action () const;
 	Glib::RefPtr<Gtk::ToggleAction> toggle_show_auto_regions_action () const;
 	
 	Gtk::Menu* _menu;
 	Gtk::ScrolledWindow _scroller;
 	Gtk::Frame _frame;
+	
 	Gtkmm2ext::DnDTreeView<boost::shared_ptr<ARDOUR::Region> > _display;
+	
 	Glib::RefPtr<Gtk::TreeStore> _model;
+	
 	bool _show_automatic_regions;
-	Editing::RegionListSortType _sort_type;
+	bool ignore_region_list_selection_change;
+	bool ignore_selected_region_change;
 	bool _no_redisplay;
+	
+	Editing::RegionListSortType _sort_type;
+
 	std::list<boost::shared_ptr<ARDOUR::Region> > tmp_region_list;
+	
+	typedef boost::unordered_map<boost::shared_ptr<ARDOUR::Region>, Gtk::TreeModel::RowReference> RegionRowMap;
+	typedef boost::unordered_map<std::string, Gtk::TreeModel::RowReference > RegionSourceMap;
+	
+	RegionRowMap region_row_map;
+	RegionSourceMap parent_regions_sources_map;
+	
 	PBD::ScopedConnection region_property_connection;
 	PBD::ScopedConnection check_new_region_connection;
-	bool ignore_region_list_selection_change;
-	bool ignore_selected_region_change;
+	
+	PBD::ScopedConnection editor_freeze_connection;
+	PBD::ScopedConnection editor_thaw_connection;
+	
         bool expanded;
 };
 
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index 3bb5d0aac8..2639662b2e 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -139,23 +139,24 @@ class Region
 	framepos_t first_frame () const { return _position; }
 	framepos_t last_frame ()  const { return _position + _length - 1; }
 
-	bool hidden ()           const { return _hidden; }
-	bool muted ()            const { return _muted; }
-	bool opaque ()           const { return _opaque; }
-	bool locked ()           const { return _locked; }
-	bool position_locked ()  const { return _position_locked; }
-	bool valid_transients () const { return _valid_transients; }
-	bool automatic ()        const { return _automatic; }
-	bool whole_file ()       const { return _whole_file; }
-	bool captured ()         const { return !(_import || _external); }
-	bool can_move ()         const { return !_position_locked; }
-	bool sync_marked ()      const { return _sync_marked; }
-	bool external ()         const { return _external; }
-	bool import ()           const { return _import; }
-	
-	Trimmable::CanTrim can_trim () const;
+	bool hidden()     const  { return _hidden; }
+	bool muted()      const  { return _muted; }
+	bool opaque ()    const  { return _opaque; }
+	bool locked()     const  { return _locked; }
+	bool position_locked() const { return _position_locked; }
+	bool valid_transients() const { return _valid_transients; }
+	bool automatic()  const  { return _automatic; }
+	bool whole_file() const  { return _whole_file; }
+	bool captured()   const  { return !(_import || _external); }
+	bool can_move()   const  { return !_position_locked; }
+	bool sync_marked() const { return _sync_marked; }
+	bool external()   const    { return _external; }
+	bool import()     const      { return _import; }
+        
+        Trimmable::CanTrim can_trim() const;
 
 	PositionLockStyle position_lock_style () const { return _position_lock_style; }
+	
 	void set_position_lock_style (PositionLockStyle ps);
 	void recompute_position_from_lock_style ();
 
@@ -175,6 +176,9 @@ class Region
 	bool region_list_equivalent (boost::shared_ptr<const Region>) const;
 	bool source_equivalent (boost::shared_ptr<const Region>) const;
 	bool uses_source (boost::shared_ptr<const Source>) const;
+	
+	std::string source_string () const;
+
 
 	/* EDITING OPERATIONS */
 
@@ -223,7 +227,7 @@ class Region
 	void source_deleted (boost::weak_ptr<Source>);
 
 	boost::shared_ptr<Source> source (uint32_t n=0) const { return _sources[ (n < _sources.size()) ? n : 0 ]; }
-	uint32_t                  n_channels()          const { return _sources.size(); }
+	uint32_t n_channels() const { return _sources.size(); }
 
 	const SourceList& sources ()        const { return _sources; }
 	const SourceList& master_sources () const { return _master_sources; }
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 0970e01b5c..293d9d391f 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -512,6 +512,7 @@ class Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionLi
 	void add_source (boost::shared_ptr<Source>);
 	void remove_source (boost::weak_ptr<Source>);
 
+	void  cleanup_regions();
 	int  cleanup_sources (CleanupReport&);
 	int  cleanup_trash_sources (CleanupReport&);
 
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 5a89707495..d711695927 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -423,6 +423,7 @@ Region::set_name (const std::string& str)
 	if (_name != str) {
 		SessionObject::set_name(str); // EMIT SIGNAL NameChanged()
 		assert(_name == str);
+
 		send_change (Properties::name);
 	}
 
@@ -490,6 +491,7 @@ Region::first_edit ()
 		_first_edit = EditChangesNothing;
 
 		send_change (Properties::name);
+
 		RegionFactory::CheckNewRegion (shared_from_this());
 	}
 }
@@ -559,6 +561,7 @@ Region::set_position_lock_style (PositionLockStyle ps)
 		}
 
 		send_change (Properties::position_lock_style);
+		
 	}
 }
 
@@ -643,7 +646,6 @@ Region::set_position_on_top (framepos_t pos, void* /*src*/)
 	/* do this even if the position is the same. this helps out
 	   a GUI that has moved its representation already.
 	*/
-
 	send_change (Properties::position);
 }
 
@@ -1023,6 +1025,7 @@ Region::set_sync_position (framepos_t absolute_pos)
 		if (!property_changes_suspended()) {
 			maybe_uncopy ();
 		}
+
 		send_change (Properties::sync_position);
 	}
 }
@@ -1035,6 +1038,7 @@ Region::clear_sync_position ()
 		if (!property_changes_suspended()) {
 			maybe_uncopy ();
 		}
+
 		send_change (Properties::sync_position);
 	}
 }
@@ -1428,6 +1432,29 @@ Region::source_equivalent (boost::shared_ptr<const Region> other) const
 	return true;
 }
 
+std::string
+Region::source_string () const
+{
+	//string res = itos(_sources.size());
+
+	char buf[64];
+
+	stringstream res;
+	res << _sources.size() << ":";
+	
+	SourceList::const_iterator i;
+
+	for (i = _sources.begin(); i != _sources.end(); ++i) {
+		res << (*i)->id() << ":";
+	}
+
+	for (i = _master_sources.begin(); i != _master_sources.end(); ++i) {
+		res << (*i)->id() << ":";
+	}
+
+	return res.str();
+}
+
 bool
 Region::uses_source (boost::shared_ptr<const Source> source) const
 {
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index cb1394740c..05fdb13bec 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -2575,6 +2575,32 @@ Session::ask_about_playlist_deletion (boost::shared_ptr<Playlist> p)
 	return r.get_value_or (1);
 }
 
+void
+Session::cleanup_regions ()
+{
+	const RegionFactory::RegionMap& regions (RegionFactory::regions());
+
+	for (RegionFactory::RegionMap::const_iterator i = regions.begin(); i != regions.end(); ++i) {
+
+		boost::shared_ptr<AudioRegion> audio_region = boost::dynamic_pointer_cast<AudioRegion>( i->second);
+		
+		if (!audio_region) {
+			continue;
+		}
+		
+		uint32_t used = playlists->region_use_count (audio_region);
+
+		if (used == 0 && !audio_region->automatic()){
+			RegionFactory::map_remove(i->second);
+		}
+	}
+
+	/* dump the history list */
+	_history.clear ();
+
+	save_state ("");
+}
+
 int
 Session::cleanup_sources (CleanupReport& rep)
 {
@@ -2999,7 +3025,7 @@ Session::controllable_by_descriptor (const ControllableDescriptor& desc)
 		break;
 
 	case ControllableDescriptor::Solo:
-		c = r->solo_control();
+                c = r->solo_control();
 		break;
 
 	case ControllableDescriptor::Mute:
diff --git a/libs/gtkmm2ext/gtk_ui.cc b/libs/gtkmm2ext/gtk_ui.cc
index 9736569053..035e892fba 100644
--- a/libs/gtkmm2ext/gtk_ui.cc
+++ b/libs/gtkmm2ext/gtk_ui.cc
@@ -147,7 +147,7 @@ UI::load_rcfile (string path, bool themechange)
 		return -1;
 	}
 
-	if (access (path.c_str(), R_OK)) {
+	if (!Glib::file_test (path, Glib::FILE_TEST_EXISTS|Glib::FILE_TEST_IS_REGULAR)) {
 		error << "UI: couldn't find rc file \""
 		      << path
 		      << '"'
@@ -155,12 +155,11 @@ UI::load_rcfile (string path, bool themechange)
 		return -1;
 	}
 
-	RC rc (path.c_str());
-	gtk_rc_reset_styles (gtk_settings_get_default());
-	//vector<string> files;
-	//files.push_back(path.c_str());
-	//RC::set_default_files(files);
-	//RC::reparse_all (Gtk::Settings::get_default(), true);
+        RC rc (path.c_str());
+        //this is buggy in gtkmm for some reason, so use C
+        //RC::reset_styles (Gtk::Settings::get_default());
+        gtk_rc_reset_styles (gtk_settings_get_default());
+
 	theme_changed.emit();
 
 	if (themechange) {