diff --git a/gtk2_ardour/ardour_ui2.cc b/gtk2_ardour/ardour_ui2.cc
index 47218e518b..d294df8036 100644
--- a/gtk2_ardour/ardour_ui2.cc
+++ b/gtk2_ardour/ardour_ui2.cc
@@ -877,7 +877,8 @@ ARDOUR_UI::editor_realized ()
 	set_size_request_to_display_given_text (speed_display_box, _("-0.55"), 2, 2);
 	const guint32 FUDGE = 25; // Combo's are stupid - they steal space from the entry for the button
 	set_size_request_to_display_given_text (shuttle_style_button, _("sprung"), 2+FUDGE, 10);
-	reset_dpi();
+	cerr << "I commented out line line 881 in ardour_ui2.cc, because it made ardour crash somewhere in Gnome::Canvas::Text" << endl;
+	//reset_dpi();
 }
 
 void
diff --git a/gtk2_ardour/canvas-flag.cc b/gtk2_ardour/canvas-flag.cc
index 232035e4cf..c40bf45648 100644
--- a/gtk2_ardour/canvas-flag.cc
+++ b/gtk2_ardour/canvas-flag.cc
@@ -5,16 +5,32 @@
 using namespace Gnome::Canvas;
 using namespace std;
 
-		
+
 void 
-CanvasFlag::set_text(string& a_text)
+CanvasFlag::delete_allocated_objects()
 {
 	if (_text) {
 		delete _text;
 		_text = 0;
 	}
 	
-	_text = new Text(*this, 0.0, 0.0, a_text);
+	if (_line) {
+		delete _line;
+		_line = 0;
+	}
+	
+	if (_rect) {
+		delete _rect;
+		_rect = 0;
+	}
+}
+
+void 
+CanvasFlag::set_text(string& a_text)
+{
+	delete_allocated_objects();
+	
+	_text = new Text(*this, 0.0, 0.0, Glib::ustring(a_text));
 	_text->property_justification() = Gtk::JUSTIFY_CENTER;
 	_text->property_fill_color_rgba() = _outline_color_rgba;
 	double flagwidth  = _text->property_text_width()  + 10.0;
@@ -33,10 +49,6 @@ CanvasFlag::set_text(string& a_text)
 
 CanvasFlag::~CanvasFlag()
 {
-	delete _line;
-	delete _rect;
-	if(_text) {
-		delete _text;
-	}
+	delete_allocated_objects();
 }
 
diff --git a/gtk2_ardour/canvas-flag.h b/gtk2_ardour/canvas-flag.h
index eb50798e8e..23fba78fee 100644
--- a/gtk2_ardour/canvas-flag.h
+++ b/gtk2_ardour/canvas-flag.h
@@ -47,6 +47,8 @@ protected:
 	guint                             _fill_color_rgba;
 	
 private:
+	void delete_allocated_objects();
+	
 	MidiRegionView&                   _region;
 	SimpleLine*                       _line;
 	SimpleRect*                       _rect;
diff --git a/gtk2_ardour/midi_region_view.cc b/gtk2_ardour/midi_region_view.cc
index 5cd1f64127..6063667210 100644
--- a/gtk2_ardour/midi_region_view.cc
+++ b/gtk2_ardour/midi_region_view.cc
@@ -658,7 +658,7 @@ MidiRegionView::find_and_insert_program_change_flags()
 						lsb = uint8_t(lsb_control->get_float(true, event_time));
 					}
 					
-					//cerr << " got msb " << int(msb) << " and lsb " << int(lsb) << endl;
+					cerr << " got msb " << int(msb) << " and lsb " << int(lsb) << " thread_id: " << pthread_self() << endl;
 					
 					patch = master_device->find_patch(
 							_custom_device_mode, 
@@ -668,9 +668,9 @@ MidiRegionView::find_and_insert_program_change_flags()
 							uint8_t(program_number)
 					);
 
-					//cerr << " got patch with name " << patch.name() << " number " << patch.number() << endl;
 				}
 				if (patch != 0) {
+					cerr << " got patch with name " << patch->name() << " number " << patch->number() << endl;
 					add_pgm_change(event_time, patch->name());
 				} else {
 					char buf[4];
@@ -1000,7 +1000,7 @@ MidiRegionView::add_pgm_change(nframes_t time, string displaytext)
 {
 	assert(time >= 0);
 	
-	// dont display notes beyond the region bounds
+	// dont display program changes beyond the region bounds
 	if (time - _region->start() >= _region->length() || time <  _region->start()) 
 		return;
 	
diff --git a/gtk2_ardour/midi_time_axis.cc b/gtk2_ardour/midi_time_axis.cc
index a8f6e3a6f4..47733f9efb 100644
--- a/gtk2_ardour/midi_time_axis.cc
+++ b/gtk2_ardour/midi_time_axis.cc
@@ -195,7 +195,7 @@ void MidiTimeAxisView::model_changed()
 	_custom_device_mode_selector.clear_items();
 	
 	for (std::list<std::string>::const_iterator i = device_modes.begin(); i != device_modes.end(); ++i) {
-		cerr << "found custom device mode " << *i << endl;
+		cerr << "found custom device mode " << *i << " thread_id: " << pthread_self() << endl;
 		_custom_device_mode_selector.append_text(*i);
 	}
 
diff --git a/libs/ardour/midi_patch_manager.cc b/libs/ardour/midi_patch_manager.cc
index bb57f4b10f..cb1ba771f4 100644
--- a/libs/ardour/midi_patch_manager.cc
+++ b/libs/ardour/midi_patch_manager.cc
@@ -50,6 +50,8 @@ void
 MidiPatchManager::refresh()
 {
 	_documents.clear();
+	_master_devices_by_model.clear();
+	_all_models.clear();
 	
 	path path_to_patches = _session->session_directory().midi_patch_path();
 	
@@ -97,4 +99,6 @@ MidiPatchManager::drop_session ()
 {
 	_session = 0;
 	_documents.clear();
+	_master_devices_by_model.clear();
+	_all_models.clear();
 }