fix some confusion when redrawing editor/mixer track/strip displays after track/bus deletion

The code relied on the idea that the order-key resync that occurs after deletion would change the order keys and thus cause
a redisplay. But since both the editor and mixer can initiate an order-key resync, the other window's resync will actually
do nothing (the order keys will already be correct). This led to the incorrect placement of material in the tracks canvas,
because the first resync triggered a redisplay while the route still existed, and then the second resync didn't cause a
redisplay (repositioning) but the canvas elements representing the track went away.

Fixed by forcing a redisplay in both editor and mixer if a route deletion is believed to be triggering a row deletion
in their underlying data models.

4 files changed, 43 insertions, 9 deletions

diff --git a/gtk2_ardour/editor_routes.cc b/gtk2_ardour/editor_routes.cc
index 38706a6525..5da4979824 100644
--- a/gtk2_ardour/editor_routes.cc
+++ b/gtk2_ardour/editor_routes.cc
@@ -70,6 +70,7 @@ EditorRoutes::EditorRoutes (Editor* e)
         , _ignore_reorder (false)
         , _no_redisplay (false)
         , _adding_routes (false)
+        , _route_deletion_in_progress (false)
         , _menu (0)
         , old_focus (0)
         , selection_countdown (0)
@@ -271,7 +272,7 @@ EditorRoutes::EditorRoutes (Editor* e)
 	active_col->set_fixed_width (30);
 	active_col->set_alignment (ALIGN_CENTER);
 	
-	_model->signal_row_deleted().connect (sigc::mem_fun (*this, &EditorRoutes::route_deleted));
+	_model->signal_row_deleted().connect (sigc::mem_fun (*this, &EditorRoutes::row_deleted));
 	_model->signal_rows_reordered().connect (sigc::mem_fun (*this, &EditorRoutes::reordered));
 
 	_display.signal_button_press_event().connect (sigc::mem_fun (*this, &EditorRoutes::button_press), false);
@@ -519,7 +520,6 @@ EditorRoutes::redisplay ()
 		/* show or hide the TimeAxisView */
 		if (visible) {
 			position += tv->show_at (position, n, &_editor->edit_controls_vbox);
-			// SHOWTRACKS
 		} else {
 			tv->hide ();
 		}
@@ -547,18 +547,38 @@ EditorRoutes::redisplay ()
 }
 
 void
-EditorRoutes::route_deleted (Gtk::TreeModel::Path const &)
+EditorRoutes::row_deleted (Gtk::TreeModel::Path const &)
 {
-	/* this happens as the second step of a DnD within the treeview as well
-	   as when a row/route is actually deleted.
+	/* this happens as the second step of a DnD within the treeview, and
+	   when a route is actually removed. we don't differentiate between
+	   the two cases.
+	   
+	   note that the sync_orders_keys() step may not actually change any
+	   RID's (e.g. the last track may be removed, so all other tracks keep
+	   the same RID), which means that no redisplay would happen. so we 
+           have to force a redisplay.
 	*/
+
 	DEBUG_TRACE (DEBUG::OrderKeys, "editor routes treeview row deleted\n");
+
+        if (_route_deletion_in_progress) {
+                suspend_redisplay ();
+        }
+
 	sync_order_keys_from_treeview ();
+
+        if (_route_deletion_in_progress) {
+                resume_redisplay ();
+        }
 }
 
 void
 EditorRoutes::reordered (TreeModel::Path const &, TreeModel::iterator const &, int* /*what*/)
 {
+	/* reordering implies that RID's will change, so sync_order_keys() will
+	   cause a redisplay.
+	*/
+
 	DEBUG_TRACE (DEBUG::OrderKeys, "editor routes treeview reordered\n");
 	sync_order_keys_from_treeview ();
 }
@@ -721,10 +741,13 @@ EditorRoutes::route_removed (TimeAxisView *tv)
 
 	TreeModel::Children rows = _model->children();
 	TreeModel::Children::iterator ri;
+	bool found = false;
 
 	for (ri = rows.begin(); ri != rows.end(); ++ri) {
 		if ((*ri)[_columns.tv] == tv) {
+                        PBD::Unwinder<bool> uw (_route_deletion_in_progress, true);
 			_model->erase (ri);
+			found = true;
 			break;
 		}
 	}
diff --git a/gtk2_ardour/editor_routes.h b/gtk2_ardour/editor_routes.h
index 9780307435..dea8da6cc0 100644
--- a/gtk2_ardour/editor_routes.h
+++ b/gtk2_ardour/editor_routes.h
@@ -73,7 +73,7 @@ private:
 	void build_menu ();
 	void show_menu ();
         void sync_treeview_from_order_keys ();
-	void route_deleted (Gtk::TreeModel::Path const &);
+	void row_deleted (Gtk::TreeModel::Path const &);
 	void visible_changed (std::string const &);
 	void active_changed (std::string const &);
 	void reordered (Gtk::TreeModel::Path const &, Gtk::TreeModel::iterator const &, int *);
@@ -156,6 +156,7 @@ private:
 	bool _ignore_reorder;
 	bool _no_redisplay;
         bool _adding_routes;
+        bool _route_deletion_in_progress;
 
 	Gtk::Menu* _menu;
         Gtk::Widget* old_focus;
diff --git a/gtk2_ardour/mixer_ui.cc b/gtk2_ardour/mixer_ui.cc
index 874f8feddf..dc0ca4b198 100644
--- a/gtk2_ardour/mixer_ui.cc
+++ b/gtk2_ardour/mixer_ui.cc
@@ -92,6 +92,9 @@ Mixer_UI::Mixer_UI ()
 	, _strip_width (Config->get_default_narrow_ms() ? Narrow : Wide)
 	, ignore_reorder (false)
 	, _following_editor_selection (false)
+        , _in_group_rebuild_or_clear (false)
+        , _route_deletion_in_progress (false)
+	, _maximised (false)
 {
 	/* allow this window to become the key focus window */
 	set_flags (CAN_FOCUS);
@@ -239,9 +242,6 @@ Mixer_UI::Mixer_UI ()
 	list_hpane.show();
 	group_display.show();
 
-	_in_group_rebuild_or_clear = false;
-	_maximised = false;
-
 	MixerStrip::CatchDeletion.connect (*this, invalidator (*this), boost::bind (&Mixer_UI::remove_strip, this, _1), gui_context());
 
         MonitorSection::setup_knob_images ();
@@ -420,6 +420,7 @@ Mixer_UI::remove_strip (MixerStrip* strip)
 	
 	for (ri = rows.begin(); ri != rows.end(); ++ri) {
 		if ((*ri)[track_columns.strip] == strip) {
+                        PBD::Unwinder<bool> uw (_route_deletion_in_progress, true);
 			track_model->erase (ri);
 			break;
 		}
@@ -997,9 +998,17 @@ Mixer_UI::track_list_delete (const Gtk::TreeModel::Path&)
 {
 	/* this happens as the second step of a DnD within the treeview as well
 	   as when a row/route is actually deleted.
+           
+           if it was a deletion then we have to force a redisplay because
+           order keys may not have changed.
 	*/
+
 	DEBUG_TRACE (DEBUG::OrderKeys, "mixer UI treeview row deleted\n");
 	sync_order_keys_from_treeview ();
+
+        if (_route_deletion_in_progress) {
+                redisplay_track_list ();
+        }
 }
 
 void
diff --git a/gtk2_ardour/mixer_ui.h b/gtk2_ardour/mixer_ui.h
index 693fd9dfa5..e5d78f2218 100644
--- a/gtk2_ardour/mixer_ui.h
+++ b/gtk2_ardour/mixer_ui.h
@@ -272,6 +272,7 @@ class Mixer_UI : public Gtk::Window, public PBD::ScopedConnectionList, public AR
 	    it during a session teardown.
 	*/
 	bool _in_group_rebuild_or_clear;
+        bool _route_deletion_in_progress;
 
 	void update_title ();
 	MixerStrip* strip_by_x (int x);