Merged with trunk R846

Removed some overly verbose debug printing


git-svn-id: svn://localhost/ardour2/branches/midi@847 d708f5d6-7413-0410-9779-e7cbd77b26cf

40 files changed, 378 insertions, 347 deletions

diff --git a/gtk2_ardour/ardbg b/gtk2_ardour/ardbg
index 9d3f5bf6c7..115db85f59 100755
--- a/gtk2_ardour/ardbg
+++ b/gtk2_ardour/ardbg
@@ -1,3 +1,4 @@
 #!/bin/sh
-source ardev_common.sh
-exec gdb ./ardour.bin "$*"
+dir=`dirname "$0"`
+source $dir/ardev_common.sh
+exec gdb gtk2_ardour/ardour.bin $*
diff --git a/gtk2_ardour/ardev b/gtk2_ardour/ardev
index 017a7e337d..751557d634 100755
--- a/gtk2_ardour/ardev
+++ b/gtk2_ardour/ardev
@@ -1,4 +1,3 @@
 #!/bin/sh
-
-source ardev_common.sh
-exec ./ardour.bin --novst $*
+source `dirname "$0"`/ardev_common.sh
+exec gtk2_ardour/ardour.bin --novst "$*"
diff --git a/gtk2_ardour/ardev_common.sh b/gtk2_ardour/ardev_common.sh
index bf644f3e84..df4bb025c0 100755
--- a/gtk2_ardour/ardev_common.sh
+++ b/gtk2_ardour/ardev_common.sh
@@ -1,8 +1,10 @@
+cd `dirname "$0"`/..
+
 #export G_DEBUG=fatal_criticals
 
-export ARDOUR_PATH=./glade:./pixmaps:.
+export ARDOUR_PATH=gtk2_ardour/glade:gtk2_ardour/pixmaps:gtk2_ardour
 
-export LD_LIBRARY_PATH=../libs/surfaces/control_protocol:../libs/ardour:../libs/midi++2:../libs/pbd:../libs/soundtouch:../libs/gtkmm2ext:../libs/sigc++2:../libs/glibmm2:../libs/gtkmm2/atk:../libs/gtkmm2/pango:../libs/gtkmm2/gdk:../libs/gtkmm2/gtk:../libs/libgnomecanvasmm:../libs/libsndfile:../libs/appleutility:$LD_LIBRARY_PATH
+export LD_LIBRARY_PATH=libs/surfaces/control_protocol:libs/ardour:libs/midi++2:libs/pbd:libs/soundtouch:libs/gtkmm2ext:libs/sigc++2:libs/glibmm2:libs/gtkmm2/atk:libs/gtkmm2/pango:libs/gtkmm2/gdk:libs/gtkmm2/gtk:libs/libgnomecanvasmm:libs/libsndfile:libs/appleutility:$LD_LIBRARY_PATH
 
 # DYLD_LIBRARY_PATH is for darwin.
 export DYLD_LIBRARY_PATH=$LD_LIBRARY_PATH
diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 34718dfb1c..de117a1399 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -546,7 +546,7 @@ void
 ARDOUR_UI::count_recenabled_diskstreams (Route& route)
 {
 	Track* track = dynamic_cast<Track*>(&route);
-	if (track && track->diskstream().record_enabled()) {
+	if (track && track->diskstream()->record_enabled()) {
 		rec_enabled_diskstreams++;
 	}
 }
@@ -869,9 +869,9 @@ ARDOUR_UI::open_session ()
 
 
 void
-ARDOUR_UI::session_add_midi_route (bool disk)
+ARDOUR_UI::session_add_midi_route (bool disk, uint32_t how_many)
 {
-	boost::shared_ptr<Route> route;
+	list<boost::shared_ptr<MidiTrack> > tracks;
 
 	if (session == 0) {
 		warning << _("You cannot add a track without a session already loaded.") << endmsg;
@@ -880,14 +880,21 @@ ARDOUR_UI::session_add_midi_route (bool disk)
 
 	try { 
 		if (disk) {
-			if ((route = session->new_midi_track (/*mode*/)) == 0) {
-				error << _("could not create new midi track") << endmsg;
+
+			tracks = session->new_midi_track (ARDOUR::Normal, how_many);
+
+			if (tracks.size() != how_many) {
+				if (how_many == 1) {
+					error << _("could not create a new midi track") << endmsg;
+				} else {
+					error << string_compose (_("could not create %1 new midi tracks"), how_many) << endmsg;
+				}
 			}
-		} else {
+		} /*else {
 			if ((route = session->new_midi_route ()) == 0) {
 				error << _("could not create new midi bus") << endmsg;
 			}
-		}
+		}*/
 	}
 
 	catch (...) {
@@ -902,23 +909,38 @@ restart JACK with more ports."));
 
 
 void
-ARDOUR_UI::session_add_audio_route (bool disk, int32_t input_channels, int32_t output_channels, ARDOUR::TrackMode mode)
+ARDOUR_UI::session_add_audio_route (bool track, int32_t input_channels, int32_t output_channels, ARDOUR::TrackMode mode, uint32_t how_many)
 {
-	boost::shared_ptr<Route> route;
+	list<boost::shared_ptr<AudioTrack> > tracks;
+	Session::RouteList routes;
 
 	if (session == 0) {
-		warning << _("You cannot add a track without a session already loaded.") << endmsg;
+		warning << _("You cannot add a track or bus without a session already loaded.") << endmsg;
 		return;
 	}
 
 	try { 
-		if (disk) {
-			if ((route = session->new_audio_track (input_channels, output_channels, mode)) == 0) {
-				error << _("could not create new audio track") << endmsg;
+		if (track) {
+			tracks = session->new_audio_track (input_channels, output_channels, mode, how_many);
+
+			if (tracks.size() != how_many) {
+				if (how_many == 1) {
+					error << _("could not create a new audio track") << endmsg;
+				} else {
+					error << string_compose (_("could not create %1 new audio tracks"), how_many) << endmsg;
+				}
 			}
+
 		} else {
-			if ((route = session->new_audio_route (input_channels, output_channels)) == 0) {
-				error << _("could not create new audio bus") << endmsg;
+
+			routes = session->new_audio_route (input_channels, output_channels, how_many);
+
+			if (routes.size() != how_many) {
+				if (how_many == 1) {
+					error << _("could not create a new audio track") << endmsg;
+				} else {
+					error << string_compose (_("could not create %1 new audio tracks"), how_many) << endmsg;
+				}
 			}
 		}
 		
@@ -946,11 +968,6 @@ restart JACK with more ports."));
 }
 
 void
-ARDOUR_UI::diskstream_added (Diskstream* ds)
-{
-}
-
-void
 ARDOUR_UI::do_transport_locate (jack_nframes_t new_position)
 {
 	jack_nframes_t _preroll;
@@ -1200,7 +1217,7 @@ ARDOUR_UI::toggle_record_enable (uint32_t dstream)
 		Track* t;
 
 		if ((t = dynamic_cast<Track*>(r.get())) != 0) {
-			t->diskstream().set_record_enabled (!t->diskstream().record_enabled());
+			t->diskstream()->set_record_enabled (!t->diskstream()->record_enabled());
 		}
 	}
 	if (session == 0) {
@@ -1326,7 +1343,6 @@ ARDOUR_UI::start_engine ()
 			   settings for a new session 
 			*/
 			session->save_state ("");
-                        session->save_history ("");
 		}
 
 		/* there is too much going on, in too many threads, for us to 
@@ -1500,7 +1516,6 @@ ARDOUR_UI::save_state_canfail (string name)
 		}
 
 		if ((ret = session->save_state (name)) != 0) {
-                        session->save_history (name);
 			return ret;
 		}
 	}
@@ -2080,15 +2095,15 @@ ARDOUR_UI::add_route ()
 	}
 
 	ResponseType r = (ResponseType) add_route_dialog->run ();
-	
+
 	add_route_dialog->hide();
 
 	switch (r) {
-	case RESPONSE_ACCEPT:
-		break;
-	default:
-		return;
-		break;
+		case RESPONSE_ACCEPT:
+			break;
+		default:
+			return;
+			break;
 	}
 
 	if ((count = add_route_dialog->count()) <= 0) {
@@ -2110,25 +2125,20 @@ ARDOUR_UI::add_route ()
 
 	/* XXX do something with name template */
 
-	while (count) {
-		if (add_route_dialog->type() == ARDOUR::DataType::MIDI) {
-			if (track) {
-				session_add_midi_track();
-			} else  {
-				MessageDialog msg (*editor,
-				   _("Sorry, MIDI Busses are not supported at this time."));
-				msg.run ();
-				//session_add_midi_bus();
-			}
-		} else if (track) {
-			session_add_audio_track (input_chan, output_chan, add_route_dialog->mode());
-		} else {
-			session_add_audio_bus (input_chan, output_chan);
+	if (add_route_dialog->type() == ARDOUR::DataType::MIDI) {
+		if (track) {
+			session_add_midi_track(count);
+		} else  {
+			MessageDialog msg (*editor,
+					_("Sorry, MIDI Busses are not supported at this time."));
+			msg.run ();
+			//session_add_midi_bus();
 		}
-		--count;
-		
-		while (Main::events_pending()) {
-			Main::iteration ();
+	} else { 
+		if (track) {
+			session_add_audio_track (input_chan, output_chan, add_route_dialog->mode(), count);
+		} else {
+			session_add_audio_bus (input_chan, output_chan, count);
 		}
 	}
 }
diff --git a/gtk2_ardour/ardour_ui.h b/gtk2_ardour/ardour_ui.h
index 0af88eec18..1f5277b5fe 100644
--- a/gtk2_ardour/ardour_ui.h
+++ b/gtk2_ardour/ardour_ui.h
@@ -189,21 +189,21 @@ class ARDOUR_UI : public Gtkmm2ext::UI
 
 	void add_route ();
 	
-	void session_add_audio_track (int input_channels, int32_t output_channels, ARDOUR::TrackMode mode) {
-		session_add_audio_route (true, input_channels, output_channels, mode);
+	void session_add_audio_track (int input_channels, int32_t output_channels, ARDOUR::TrackMode mode, uint32_t how_many) {
+		session_add_audio_route (true, input_channels, output_channels, mode, how_many);
 	}
 
-	void session_add_audio_bus (int input_channels, int32_t output_channels) {
-		session_add_audio_route (false, input_channels, output_channels, ARDOUR::Normal);
+	void session_add_audio_bus (int input_channels, int32_t output_channels, uint32_t how_many) {
+		session_add_audio_route (false, input_channels, output_channels, ARDOUR::Normal, how_many);
 	}
 
-	void session_add_midi_track () {
-		session_add_midi_route (true);
+	void session_add_midi_track (uint32_t how_many) {
+		session_add_midi_route (true, how_many);
 	}
 
-	void session_add_midi_bus () {
+	/*void session_add_midi_bus () {
 		session_add_midi_route (false);
-	}
+	}*/
 
 	void set_engine (ARDOUR::AudioEngine&);
 
@@ -526,8 +526,6 @@ class ARDOUR_UI : public Gtkmm2ext::UI
 	sigc::connection point_one_second_connection;
 	sigc::connection point_zero_one_second_connection;
 
-	void diskstream_added (ARDOUR::Diskstream*);
-
 	gint session_menu (GdkEventButton *);
 
 	bool _will_create_new_session_automatically;
@@ -540,8 +538,8 @@ class ARDOUR_UI : public Gtkmm2ext::UI
 
 	void save_template ();
 
-	void session_add_audio_route (bool disk, int32_t input_channels, int32_t output_channels, ARDOUR::TrackMode mode);
-	void session_add_midi_route (bool disk);
+	void session_add_audio_route (bool disk, int32_t input_channels, int32_t output_channels, ARDOUR::TrackMode mode, uint32_t how_many);
+	void session_add_midi_route (bool disk, uint32_t how_many);
 
 	void set_transport_sensitivity (bool);
 
diff --git a/gtk2_ardour/ardour_ui_dialogs.cc b/gtk2_ardour/ardour_ui_dialogs.cc
index 5a1ec87462..c90480c1dd 100644
--- a/gtk2_ardour/ardour_ui_dialogs.cc
+++ b/gtk2_ardour/ardour_ui_dialogs.cc
@@ -76,10 +76,6 @@ ARDOUR_UI::connect_to_session (Session *s)
 	rec_button.set_sensitive (true);
 	shuttle_box.set_sensitive (true);
 	
-	if (session->n_diskstreams() == 0) {
-		session->DiskstreamAdded.connect (mem_fun(*this, &ARDOUR_UI::diskstream_added));
-	}
-
 	if (connection_editor) {
 		connection_editor->set_session (s);
 	}
@@ -156,7 +152,6 @@ ARDOUR_UI::unload_session ()
 			
 		case 1:
 			session->save_state ("");
-                        session->save_history ("");
 			break;
 		}
 	}
diff --git a/gtk2_ardour/ardour_ui_ed.cc b/gtk2_ardour/ardour_ui_ed.cc
index fc5ffb6e9c..2fe34127dc 100644
--- a/gtk2_ardour/ardour_ui_ed.cc
+++ b/gtk2_ardour/ardour_ui_ed.cc
@@ -194,14 +194,14 @@ ARDOUR_UI::install_actions ()
 	act = ActionManager::register_action (common_actions, X_("About"), _("About"),  mem_fun(*this, &ARDOUR_UI::show_splash));
 	act = ActionManager::register_toggle_action (common_actions, X_("ToggleColorManager"), _("Colors"), mem_fun(*this, &ARDOUR_UI::toggle_color_manager));
 	ActionManager::session_sensitive_actions.push_back (act);
-	act = ActionManager::register_action (common_actions, X_("AddAudioTrack"), _("Add Audio Track"), bind (mem_fun(*this, &ARDOUR_UI::session_add_audio_track), 1, 1, ARDOUR::Normal));
+	act = ActionManager::register_action (common_actions, X_("AddAudioTrack"), _("Add Audio Track"), bind (mem_fun(*this, &ARDOUR_UI::session_add_audio_track), 1, 1, ARDOUR::Normal, 1));
 	ActionManager::session_sensitive_actions.push_back (act);
-	act = ActionManager::register_action (common_actions, X_("AddAudioBus"), _("Add Audio Bus"), bind (mem_fun(*this, &ARDOUR_UI::session_add_audio_bus), 1, 1));
+	act = ActionManager::register_action (common_actions, X_("AddAudioBus"), _("Add Audio Bus"), bind (mem_fun(*this, &ARDOUR_UI::session_add_audio_bus), 1, 1, 1));
 	ActionManager::session_sensitive_actions.push_back (act);
-	act = ActionManager::register_action (common_actions, X_("AddMIDITrack"), _("Add MIDI Track"), (mem_fun(*this, &ARDOUR_UI::session_add_midi_track)));
-	ActionManager::session_sensitive_actions.push_back (act);
-	act = ActionManager::register_action (common_actions, X_("AddMidiBus"), _("Add Midi Bus"), mem_fun(*this, &ARDOUR_UI::session_add_midi_bus));
+	act = ActionManager::register_action (common_actions, X_("AddMIDITrack"), _("Add MIDI Track"), bind (mem_fun(*this, &ARDOUR_UI::session_add_midi_track), 1));
 	ActionManager::session_sensitive_actions.push_back (act);
+	//act = ActionManager::register_action (common_actions, X_("AddMidiBus"), _("Add Midi Bus"), mem_fun(*this, &ARDOUR_UI::session_add_midi_bus));
+	//ActionManager::session_sensitive_actions.push_back (act);
 	act = ActionManager::register_action (common_actions, X_("Save"), _("Save"),  bind (mem_fun(*this, &ARDOUR_UI::save_state), string("")));
 	ActionManager::session_sensitive_actions.push_back (act);
 	act = ActionManager::register_action (common_actions, X_("RemoveLastCapture"), _("Remove Last Capture"), mem_fun(*this, &ARDOUR_UI::remove_last_capture));
diff --git a/gtk2_ardour/audio_region_view.cc b/gtk2_ardour/audio_region_view.cc
index acde408c6b..93af5b3ec0 100644
--- a/gtk2_ardour/audio_region_view.cc
+++ b/gtk2_ardour/audio_region_view.cc
@@ -928,13 +928,13 @@ AudioRegionView::add_gain_point_event (ArdourCanvas::Item *item, GdkEvent *ev)
 		XMLNode &before = audio_region().get_state();
 		audio_region().set_envelope_active(true);
 		XMLNode &after = audio_region().get_state();
-		trackview.session().add_command (new MementoCommand<AudioRegion>(audio_region(), before, after));
+		trackview.session().add_command (new MementoCommand<AudioRegion>(audio_region(), &before, &after));
 	}
 
 	audio_region().envelope().add (fx, y);
 	
 	XMLNode &after = audio_region().envelope().get_state();
-	trackview.session().add_command (new MementoCommand<Curve>(audio_region().envelope(), before, after));
+	trackview.session().add_command (new MementoCommand<Curve>(audio_region().envelope(), &before, &after));
 	trackview.session().commit_reversible_command ();
 }
 
diff --git a/gtk2_ardour/audio_streamview.cc b/gtk2_ardour/audio_streamview.cc
index 523395c503..83d1825ef5 100644
--- a/gtk2_ardour/audio_streamview.cc
+++ b/gtk2_ardour/audio_streamview.cc
@@ -224,7 +224,7 @@ AudioStreamView::playlist_modified ()
 }
 
 void
-AudioStreamView::playlist_changed (Diskstream *ds)
+AudioStreamView::playlist_changed (boost::shared_ptr<Diskstream> ds)
 {
 	ENSURE_GUI_THREAD (bind (mem_fun (*this, &AudioStreamView::playlist_changed), ds));
 
@@ -398,7 +398,7 @@ AudioStreamView::setup_rec_box ()
 				rec_data_ready_connections.clear();
 					
 				// FIXME
-				AudioDiskstream* ads = dynamic_cast<AudioDiskstream*>(_trackview.get_diskstream());
+				boost::shared_ptr<AudioDiskstream> ads = boost::dynamic_pointer_cast<AudioDiskstream>(_trackview.get_diskstream());
 				assert(ads);
 
 				for (uint32_t n=0; n < ads->n_channels().get(DataType::AUDIO); ++n) {
@@ -430,8 +430,8 @@ AudioStreamView::setup_rec_box ()
 			AudioTrack* at;
 
 			at = _trackview.audio_track(); /* we know what it is already */
-			AudioDiskstream& ds = at->audio_diskstream();
-			jack_nframes_t frame_pos = ds.current_capture_start ();
+			boost::shared_ptr<AudioDiskstream> ds = at->audio_diskstream();
+			jack_nframes_t frame_pos = ds->current_capture_start ();
 			gdouble xstart = _trackview.editor.frame_to_pixel (frame_pos);
 			gdouble xend;
 			uint32_t fill_color;
diff --git a/gtk2_ardour/audio_streamview.h b/gtk2_ardour/audio_streamview.h
index 979240bd50..cf66637b9b 100644
--- a/gtk2_ardour/audio_streamview.h
+++ b/gtk2_ardour/audio_streamview.h
@@ -87,7 +87,7 @@ class AudioStreamView : public StreamView
 	void undisplay_diskstream ();
 	void redisplay_diskstream ();
 	void playlist_modified ();
-	void playlist_changed (ARDOUR::Diskstream *ds);
+	void playlist_changed (boost::shared_ptr<ARDOUR::Diskstream>);
 
 	void add_crossfade (ARDOUR::Crossfade*);
 	void remove_crossfade (ARDOUR::Crossfade*);
diff --git a/gtk2_ardour/automation_line.cc b/gtk2_ardour/automation_line.cc
index f3e30c4523..c0ba957af8 100644
--- a/gtk2_ardour/automation_line.cc
+++ b/gtk2_ardour/automation_line.cc
@@ -244,6 +244,9 @@ AutomationLine::AutomationLine (const string & name, TimeAxisView& tv, ArdourCan
 	line->signal_event().connect (mem_fun (*this, &AutomationLine::event_handler));
 
 	alist.StateChanged.connect (mem_fun(*this, &AutomationLine::list_changed));
+
+        trackview.session().register_with_memento_command_factory(_id, this);
+
 }
 
 AutomationLine::~AutomationLine ()
@@ -888,7 +891,7 @@ AutomationLine::start_drag (ControlPoint* cp, float fraction)
 	}
 
 	trackview.editor.current_session()->begin_reversible_command (str);
-	trackview.editor.current_session()->add_command (new MementoUndoCommand<AutomationLine>(*this, get_state()));
+	trackview.editor.current_session()->add_command (new MementoCommand<AutomationLine>(*this, &get_state(), 0));
 	
 	first_drag_fraction = fraction;
 	last_drag_fraction = fraction;
@@ -937,7 +940,7 @@ AutomationLine::end_drag (ControlPoint* cp)
 
 		update_pending = false;
 
-		trackview.editor.current_session()->add_command (new MementoRedoCommand<AutomationLine>(*this, get_state()));
+		trackview.editor.current_session()->add_command (new MementoCommand<AutomationLine>(*this, 0, &get_state()));
 		trackview.editor.current_session()->commit_reversible_command ();
 		trackview.editor.current_session()->set_dirty ();
 	}
@@ -1018,7 +1021,7 @@ AutomationLine::remove_point (ControlPoint& cp)
 
 	alist.erase (mr.start, mr.end);
 
-	trackview.editor.current_session()->add_command(new MementoCommand<AutomationLine>(*this, before, get_state()));
+	trackview.editor.current_session()->add_command(new MementoCommand<AutomationLine>(*this, &before, &get_state()));
 	trackview.editor.current_session()->commit_reversible_command ();
 	trackview.editor.current_session()->set_dirty ();
 }
@@ -1228,7 +1231,7 @@ AutomationLine::clear ()
 	/* parent must create command */
         XMLNode &before = get_state();
 	alist.clear();
-	trackview.editor.current_session()->add_command (new MementoCommand<AutomationLine>(*this, before, get_state()));
+	trackview.editor.current_session()->add_command (new MementoCommand<AutomationLine>(*this, &before, &get_state()));
 	trackview.editor.current_session()->commit_reversible_command ();
 	trackview.editor.current_session()->set_dirty ();
 }
diff --git a/gtk2_ardour/automation_time_axis.cc b/gtk2_ardour/automation_time_axis.cc
index 7025a11178..80ed2acd16 100644
--- a/gtk2_ardour/automation_time_axis.cc
+++ b/gtk2_ardour/automation_time_axis.cc
@@ -482,7 +482,7 @@ AutomationTimeAxisView::cut_copy_clear_one (AutomationLine& line, Selection& sel
 	case Cut:
 		if ((what_we_got = alist.cut (selection.time.front().start, selection.time.front().end)) != 0) {
 			editor.get_cut_buffer().add (what_we_got);
-			_session.add_command(new MementoCommand<AutomationList>(alist, before, alist.get_state()));
+			_session.add_command(new MementoCommand<AutomationList>(alist, &before, &alist.get_state()));
 			ret = true;
 		}
 		break;
@@ -494,7 +494,7 @@ AutomationTimeAxisView::cut_copy_clear_one (AutomationLine& line, Selection& sel
 
 	case Clear:
 		if ((what_we_got = alist.cut (selection.time.front().start, selection.time.front().end)) != 0) {
-			_session.add_command(new MementoCommand<AutomationList>(alist, before, alist.get_state()));
+			_session.add_command(new MementoCommand<AutomationList>(alist, &before, &alist.get_state()));
 			delete what_we_got;
 			what_we_got = 0;
 			ret = true;
@@ -526,7 +526,7 @@ AutomationTimeAxisView::reset_objects_one (AutomationLine& line, PointSelection&
 {
 	AutomationList& alist (line.the_list());
 
-	_session.add_command (new MementoUndoCommand<AutomationList>(alist, alist.get_state()));
+	_session.add_command (new MementoCommand<AutomationList>(alist, &alist.get_state(), 0));
 
 	for (PointSelection::iterator i = selection.begin(); i != selection.end(); ++i) {
 
@@ -569,7 +569,7 @@ AutomationTimeAxisView::cut_copy_clear_objects_one (AutomationLine& line, PointS
 		case Cut:
 			if ((what_we_got = alist.cut ((*i).start, (*i).end)) != 0) {
 				editor.get_cut_buffer().add (what_we_got);
-				_session.add_command (new MementoCommand<AutomationList>(alist, before, alist.get_state()));
+				_session.add_command (new MementoCommand<AutomationList>(alist, &before, &alist.get_state()));
 				ret = true;
 			}
 			break;
@@ -581,7 +581,7 @@ AutomationTimeAxisView::cut_copy_clear_objects_one (AutomationLine& line, PointS
 			
 		case Clear:
 			if ((what_we_got = alist.cut ((*i).start, (*i).end)) != 0) {
-				_session.add_command (new MementoCommand<AutomationList>(alist, before, alist.get_state()));
+				_session.add_command (new MementoCommand<AutomationList>(alist, &before, &alist.get_state()));
 				delete what_we_got;
 				what_we_got = 0;
 				ret = true;
@@ -640,7 +640,7 @@ AutomationTimeAxisView::paste_one (AutomationLine& line, jack_nframes_t pos, flo
 
         XMLNode &before = alist.get_state();
 	alist.paste (copy, pos, times);
-	_session.add_command (new MementoCommand<AutomationList>(alist, before, alist.get_state()));
+	_session.add_command (new MementoCommand<AutomationList>(alist, &before, &alist.get_state()));
 
 	return true;
 }
diff --git a/gtk2_ardour/axis_view.h b/gtk2_ardour/axis_view.h
index 12b7d32188..4ae8f8d46e 100644
--- a/gtk2_ardour/axis_view.h
+++ b/gtk2_ardour/axis_view.h
@@ -84,8 +84,6 @@ class AxisView : public virtual Selectable
 
 	Gtk::Label name_label;
 
-	bool _selected;
-
 	bool _marked_for_display;
 	
 }; /* class AxisView */
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 5c3847730c..eceaf24d38 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -705,6 +705,7 @@ Editor::Editor (AudioEngine& eng)
 	ControlProtocol::ScrollTimeline.connect (mem_fun (*this, &Editor::control_scroll));
 	constructed = true;
 	instant_save ();
+
 }
 
 Editor::~Editor()
@@ -1339,6 +1340,9 @@ Editor::connect_to_session (Session *t)
 		no_route_list_redisplay = false;
 		redisplay_route_list ();
 	}
+
+        /* register for undo history */
+        session->register_with_memento_command_factory(_id, this);
 }
 
 void
@@ -1592,7 +1596,7 @@ Editor::build_track_region_context_menu (jack_nframes_t frame)
 	AudioTimeAxisView* atv = dynamic_cast<AudioTimeAxisView*> (clicked_axisview);
 
 	if (atv) {
-		Diskstream* ds;
+		boost::shared_ptr<Diskstream> ds;
 		Playlist* pl;
 		
 		if ((ds = atv->get_diskstream()) && ((pl = ds->playlist()))) {
@@ -1619,7 +1623,7 @@ Editor::build_track_crossfade_context_menu (jack_nframes_t frame)
 	AudioTimeAxisView* atv = dynamic_cast<AudioTimeAxisView*> (clicked_axisview);
 
 	if (atv) {
-		Diskstream* ds;
+		boost::shared_ptr<Diskstream> ds;
 		Playlist* pl;
 		AudioPlaylist* apl;
 
@@ -2888,7 +2892,7 @@ void
 Editor::commit_reversible_command ()
 {
 	if (session) {
-		session->commit_reversible_command (new MementoCommand<Editor>(*this, *before, get_state()));
+		session->commit_reversible_command (new MementoCommand<Editor>(*this, before, &get_state()));
 	}
 }
 
@@ -3016,7 +3020,7 @@ Editor::mapped_set_selected_regionview_from_click (RouteTimeAxisView& tv, uint32
 	Playlist* pl;
 	vector<Region*> results;
 	RegionView* marv;
-	Diskstream* ds;
+	boost::shared_ptr<Diskstream> ds;
 
 	if ((ds = tv.get_diskstream()) == 0) {
 		/* bus */
@@ -3242,7 +3246,7 @@ Editor::set_selected_regionview_from_region_list (Region& region, Selection::Ope
 			Playlist* pl;
 			vector<Region*> results;
 			RegionView* marv;
-			Diskstream* ds;
+			boost::shared_ptr<Diskstream> ds;
 			
 			if ((ds = tatv->get_diskstream()) == 0) {
 				/* bus */
@@ -3750,10 +3754,12 @@ Editor::get_valid_views (TimeAxisView* track, RouteGroup* group)
 void
 Editor::set_zoom_focus (ZoomFocus f)
 {
+	vector<string> txt = internationalize (zoom_focus_strings);
+	zoom_focus_selector.set_active_text (txt[(int)f]);
+	
 	if (zoom_focus != f) {
 		zoom_focus = f;
-		vector<string> txt = internationalize (zoom_focus_strings);
-		zoom_focus_selector.set_active_text (txt[(int)f]);
+
 		ZoomFocusChanged (); /* EMIT_SIGNAL */
 
 		instant_save ();
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 40ece795b1..970acdc3a9 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -466,7 +466,7 @@ class Editor : public PublicEditor
 	void add_crossfade_context_items (AudioStreamView*, ARDOUR::Crossfade*, Gtk::Menu_Helpers::MenuList&, bool many);
 	void add_selection_context_items (Gtk::Menu_Helpers::MenuList&);
 
-	void handle_new_route (boost::shared_ptr<ARDOUR::Route>);
+	void handle_new_route (ARDOUR::Session::RouteList&);
 	void remove_route (TimeAxisView *);
 	bool route_removal;
 
diff --git a/gtk2_ardour/editor_audio_import.cc b/gtk2_ardour/editor_audio_import.cc
index de256ce0e6..2b704e7372 100644
--- a/gtk2_ardour/editor_audio_import.cc
+++ b/gtk2_ardour/editor_audio_import.cc
@@ -318,13 +318,13 @@ Editor::finish_bringing_in_audio (AudioRegion& region, uint32_t in_chans, uint32
 		
 	case ImportToTrack:
 		if (track) {
-			Playlist* playlist  = track->diskstream().playlist();
+			Playlist* playlist  = track->diskstream()->playlist();
 			
 			AudioRegion* copy = new AudioRegion (region);
 			begin_reversible_command (_("insert sndfile"));
                         XMLNode &before = playlist->get_state();
 			playlist->add_region (*copy, pos);
-			session->add_command (new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+			session->add_command (new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 			commit_reversible_command ();
 
 			pos += region.length();
@@ -333,17 +333,21 @@ Editor::finish_bringing_in_audio (AudioRegion& region, uint32_t in_chans, uint32
 		
 	case ImportAsTrack:
 	{ 
-		boost::shared_ptr<AudioTrack> at (session->new_audio_track (in_chans, out_chans, Normal));
-		copy = new AudioRegion (region);
-		at->diskstream().playlist()->add_region (*copy, pos);
+		list<boost::shared_ptr<AudioTrack> > at (session->new_audio_track (in_chans, out_chans, Normal, 1));
+		if (!at.empty()) {
+			copy = new AudioRegion (region);
+			at.front()->diskstream()->playlist()->add_region (*copy, pos);
+		}
 		break;
 	}
 
 	case ImportAsTapeTrack:
 	{
-		boost::shared_ptr<AudioTrack> at (session->new_audio_track (in_chans, out_chans, Destructive));
-		copy = new AudioRegion (region);
-		at->diskstream().playlist()->add_region (*copy, pos);
+		list<boost::shared_ptr<AudioTrack> > at (session->new_audio_track (in_chans, out_chans, Destructive));
+		if (!at.empty()) {
+			copy = new AudioRegion (region);
+			at.front()->diskstream()->playlist()->add_region (*copy, pos);
+		}
 		break;
 	}
 	}
diff --git a/gtk2_ardour/editor_keyboard.cc b/gtk2_ardour/editor_keyboard.cc
index f48d860d15..95289c7f5a 100644
--- a/gtk2_ardour/editor_keyboard.cc
+++ b/gtk2_ardour/editor_keyboard.cc
@@ -108,7 +108,7 @@ Editor::kbd_mute_unmute_region ()
 	    entered_regionview->region().set_muted (!entered_regionview->region().muted());
 		
 		XMLNode &after = entered_regionview->region().playlist()->get_state();
-		session->add_command (new MementoCommand<ARDOUR::Playlist>(*(entered_regionview->region().playlist()), before, after));
+		session->add_command (new MementoCommand<ARDOUR::Playlist>(*(entered_regionview->region().playlist()), &before, &after));
 		commit_reversible_command();
 	}
 }
diff --git a/gtk2_ardour/editor_markers.cc b/gtk2_ardour/editor_markers.cc
index ccc1415888..40f00c2e10 100644
--- a/gtk2_ardour/editor_markers.cc
+++ b/gtk2_ardour/editor_markers.cc
@@ -294,7 +294,7 @@ Editor::mouse_add_new_marker (jack_nframes_t where)
                 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->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 		session->commit_reversible_command ();
 	}
 }
@@ -334,7 +334,7 @@ Editor::really_remove_marker (Location* loc)
 	XMLNode &before = session->locations()->get_state();
 	session->locations()->remove (loc);
 	XMLNode &after = session->locations()->get_state();
-	session->add_command (new MementoCommand<Locations>(*(session->locations()), before, after));
+	session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 	return FALSE;
 }
@@ -847,7 +847,7 @@ Editor::marker_menu_rename ()
 	loc->set_name (txt);
 	
         XMLNode &after = session->locations()->get_state();
-	session->add_command (new MementoCommand<Locations>(*(session->locations()), before, after));
+	session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	commit_reversible_command ();
 }
 
@@ -876,14 +876,14 @@ Editor::new_transport_marker_menu_set_loop ()
 		session->locations()->add (loc, true);
 		session->set_auto_loop_location (loc);
                 XMLNode &after = session->locations()->get_state();
-		session->add_command (new MementoCommand<Locations>(*(session->locations()), before, after));
+		session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	}
 	else {
                 XMLNode &before = tll->get_state();
 		tll->set_hidden (false, this);
 		tll->set (temp_location->start(), temp_location->end());
                 XMLNode &after = tll->get_state();
-                session->add_command (new MementoCommand<Location>(*tll, before, after));
+                session->add_command (new MementoCommand<Location>(*tll, &before, &after));
 	}
 	
 	commit_reversible_command ();
@@ -904,13 +904,13 @@ Editor::new_transport_marker_menu_set_punch ()
 		session->locations()->add (tpl, true);
 		session->set_auto_punch_location (tpl);
                 XMLNode &after = session->locations()->get_state();
-		session->add_command (new MementoCommand<Locations>(*(session->locations()), before, after));
+		session->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	} else {
                 XMLNode &before = tpl->get_state();
 		tpl->set_hidden(false, this);
 		tpl->set(temp_location->start(), temp_location->end());
                 XMLNode &after = tpl->get_state();
-                session->add_command (new MementoCommand<Location>(*tpl, before, after));
+                session->add_command (new MementoCommand<Location>(*tpl, &before, &after));
 	}
 	
 	commit_reversible_command ();
diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index eb0bd432e3..df2c1d101c 100644
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -1825,8 +1825,8 @@ Editor::fade_in_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent* even
 
         XMLNode &after = arv->audio_region().get_state();
         session->add_command(new MementoCommand<ARDOUR::AudioRegion>(arv->audio_region(),
-                                                                     before,
-                                                                     after));
+                                                                     &before,
+                                                                     &after));
 	commit_reversible_command ();
 	fade_in_drag_motion_callback (item, event);
 }
@@ -1921,7 +1921,7 @@ Editor::fade_out_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent* eve
 	arv->audio_region().set_fade_out_length (fade_length);
 
         XMLNode &after = arv->region().get_state();
-        session->add_command(new MementoCommand<ARDOUR::Region>(arv->region(), before, after));
+        session->add_command(new MementoCommand<ARDOUR::Region>(arv->region(), &before, &after));
 	commit_reversible_command ();
 
 	fade_out_drag_motion_callback (item, event);
@@ -2176,7 +2176,7 @@ Editor::marker_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent* event
 	}
 
 	XMLNode &after = session->locations()->get_state();
-	session->add_command(new MementoCommand<Locations>(*(session->locations()), before, after));
+	session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	commit_reversible_command ();
 	
 	marker_drag_line->hide();
@@ -2293,7 +2293,7 @@ Editor::meter_marker_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent*
                 XMLNode &before = map.get_state();
 		map.add_meter (marker->meter(), when);
 		XMLNode &after = map.get_state();
-                session->add_command(new MementoCommand<TempoMap>(map, before, after));
+                session->add_command(new MementoCommand<TempoMap>(map, &before, &after));
 		commit_reversible_command ();
 		
 		// delete the dummy marker we used for visual representation of copying.
@@ -2304,7 +2304,7 @@ Editor::meter_marker_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent*
 		XMLNode &before = map.get_state();
 		map.move_meter (marker->meter(), when);
 		XMLNode &after = map.get_state();
-                session->add_command(new MementoCommand<TempoMap>(map, before, after));
+                session->add_command(new MementoCommand<TempoMap>(map, &before, &after));
 		commit_reversible_command ();
 	}
 }
@@ -2425,7 +2425,7 @@ Editor::tempo_marker_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent*
 		XMLNode &before = map.get_state();
 		map.add_tempo (marker->tempo(), when);
 		XMLNode &after = map.get_state();
-		session->add_command (new MementoCommand<TempoMap>(map, before, after));
+		session->add_command (new MementoCommand<TempoMap>(map, &before, &after));
 		commit_reversible_command ();
 		
 		// delete the dummy marker we used for visual representation of copying.
@@ -2436,7 +2436,7 @@ Editor::tempo_marker_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent*
                 XMLNode &before = map.get_state();
 		map.move_tempo (marker->tempo(), when);
                 XMLNode &after = map.get_state();
-                session->add_command (new MementoCommand<TempoMap>(map, before, after));
+                session->add_command (new MementoCommand<TempoMap>(map, &before, &after));
 		commit_reversible_command ();
 	}
 }
@@ -2800,7 +2800,7 @@ Editor::region_drag_motion_callback (ArdourCanvas::Item* item, GdkEvent* event)
 			
 			insert_result = affected_playlists.insert (to_playlist);
 			if (insert_result.second) {
-				session->add_command (new MementoUndoCommand<Playlist>(*to_playlist, to_playlist->get_state()));
+				session->add_command (new MementoCommand<Playlist>(*to_playlist, &to_playlist->get_state(), 0));
 			}
 			
 			latest_regionview = 0;
@@ -3238,7 +3238,7 @@ Editor::region_drag_motion_callback (ArdourCanvas::Item* item, GdkEvent* event)
 					insert_result = motion_frozen_playlists.insert (pl);
 					if (insert_result.second) {
 						pl->freeze();
-						session->add_command(new MementoUndoCommand<Playlist>(*pl, pl->get_state()));
+						session->add_command(new MementoCommand<Playlist>(*pl, &pl->get_state(), 0));
 					}
 				}
 			}
@@ -3366,7 +3366,7 @@ Editor::region_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent* event
 			insert_result = motion_frozen_playlists.insert(to_playlist);
 			if (insert_result.second) {
 				to_playlist->freeze();
-                                session->add_command(new MementoUndoCommand<Playlist>(*to_playlist, to_playlist->get_state()));
+                                session->add_command(new MementoCommand<Playlist>(*to_playlist, &to_playlist->get_state(), 0));
 			}
 
 		}
@@ -3448,7 +3448,7 @@ Editor::region_drag_finished_callback (ArdourCanvas::Item* item, GdkEvent* event
   out:
 	for (set<Playlist*>::iterator p = motion_frozen_playlists.begin(); p != motion_frozen_playlists.end(); ++p) {
 		(*p)->thaw ();
-		session->add_command (new MementoRedoCommand<Playlist>(*(*p), (*p)->get_state()));
+		session->add_command (new MementoCommand<Playlist>(*(*p), 0, & (*p)->get_state()));
 	}
 
 	motion_frozen_playlists.clear ();
@@ -3643,10 +3643,10 @@ Editor::start_selection_grab (ArdourCanvas::Item* item, GdkEvent* event)
 
 	Playlist* playlist = clicked_axisview->playlist();
 
-        before = &(playlist->get_state());
+        XMLNode *before = &(playlist->get_state());
 	clicked_axisview->playlist()->add_region (*region, selection->time[clicked_selection].start);
-        XMLNode &after = playlist->get_state();
-	session->add_command(new MementoCommand<Playlist>(*playlist, *before, after));
+        XMLNode *after = &(playlist->get_state());
+	session->add_command(new MementoCommand<Playlist>(*playlist, before, after));
 
 	commit_reversible_command ();
 	
@@ -4013,7 +4013,7 @@ Editor::trim_motion_callback (ArdourCanvas::Item* item, GdkEvent* event)
 			Playlist * pl = (*i)->region().playlist();
 			insert_result = motion_frozen_playlists.insert (pl);
 			if (insert_result.second) {
-                                session->add_command(new MementoUndoCommand<Playlist>(*pl, pl->get_state()));
+                                session->add_command(new MementoCommand<Playlist>(*pl, &pl->get_state(), 0));
 			}
 		}
 	}
@@ -4203,7 +4203,7 @@ Editor::trim_finished_callback (ArdourCanvas::Item* item, GdkEvent* event)
 		
 		for (set<Playlist*>::iterator p = motion_frozen_playlists.begin(); p != motion_frozen_playlists.end(); ++p) {
 			//(*p)->thaw ();
-                        session->add_command (new MementoRedoCommand<Playlist>(*(*p), (*p)->get_state()));
+                        session->add_command (new MementoCommand<Playlist>(*(*p), 0, &(*p)->get_state()));
                 }
 		
 		motion_frozen_playlists.clear ();
@@ -4241,7 +4241,7 @@ Editor::point_trim (GdkEvent* event)
                                         XMLNode &before = pl->get_state();
 					(*i)->region().trim_front (new_bound, this);	
                                         XMLNode &after = pl->get_state();
-                                        session->add_command(new MementoCommand<Playlist>(*pl, before, after));
+                                        session->add_command(new MementoCommand<Playlist>(*pl, &before, &after));
 				}
 			}
 
@@ -4252,7 +4252,7 @@ Editor::point_trim (GdkEvent* event)
 				XMLNode &before = pl->get_state();
 				rv->region().trim_front (new_bound, this);	
                                 XMLNode &after = pl->get_state();
-				session->add_command(new MementoCommand<Playlist>(*pl, before, after));
+				session->add_command(new MementoCommand<Playlist>(*pl, &before, &after));
 			}
 		}
 
@@ -4272,7 +4272,7 @@ Editor::point_trim (GdkEvent* event)
 					XMLNode &before = pl->get_state();
 					(*i)->region().trim_end (new_bound, this);
 					XMLNode &after = pl->get_state();
-					session->add_command(new MementoCommand<Playlist>(*pl, before, after));
+					session->add_command(new MementoCommand<Playlist>(*pl, &before, &after));
 				}
 			}
 
@@ -4283,7 +4283,7 @@ Editor::point_trim (GdkEvent* event)
 				XMLNode &before = pl->get_state();
 				rv->region().trim_end (new_bound, this);
                                 XMLNode &after = pl->get_state();
-				session->add_command (new MementoCommand<Playlist>(*pl, before, after));
+				session->add_command (new MementoCommand<Playlist>(*pl, &before, &after));
 			}
 		}
 
@@ -4306,7 +4306,7 @@ Editor::thaw_region_after_trim (RegionView& rv)
 
 	region.thaw (_("trimmed region"));
         XMLNode &after = region.playlist()->get_state();
-	session->add_command (new MementoRedoCommand<Playlist>(*(region.playlist()), after));
+	session->add_command (new MementoCommand<Playlist>(*(region.playlist()), 0, &after));
 
 	AudioRegionView* arv = dynamic_cast<AudioRegionView*>(&rv);
 	if (arv)
@@ -4451,7 +4451,7 @@ Editor::end_range_markerbar_op (ArdourCanvas::Item* item, GdkEvent* event)
 			newloc = new Location(temp_location->start(), temp_location->end(), "unnamed", Location::IsRangeMarker);
 			session->locations()->add (newloc, true);
                         XMLNode &after = session->locations()->get_state();
-			session->add_command(new MementoCommand<Locations>(*(session->locations()), before, after));
+			session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 			commit_reversible_command ();
 			
 			range_bar_drag_rect->hide();
@@ -4834,7 +4834,7 @@ Editor::mouse_brush_insert_region (RegionView* rv, jack_nframes_t pos)
         XMLNode &before = playlist->get_state();
 	playlist->add_region (*(new AudioRegion (arv->audio_region())), (jack_nframes_t) (pos * speed));
         XMLNode &after = playlist->get_state();
-	session->add_command(new MementoCommand<Playlist>(*playlist, before, after));
+	session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
 	
 	// playlist is frozen, so we have to update manually
 	
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 7115bfe634..2532222c0d 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -213,7 +213,7 @@ Editor::split_regions_at (jack_nframes_t where, RegionSelection& regions)
                         XMLNode &before = pl->get_state();
 			pl->split_region ((*a)->region(), where);
                         XMLNode &after = pl->get_state();
-                        session->add_command(new MementoCommand<Playlist>(*pl, before, after));
+                        session->add_command(new MementoCommand<Playlist>(*pl, &before, &after));
 		}
 
 		a = tmp;
@@ -236,7 +236,7 @@ Editor::remove_clicked_region ()
         XMLNode &before = playlist->get_state();
 	playlist->remove_region (&clicked_regionview->region());
         XMLNode &after = playlist->get_state();
-	session->add_command(new MementoCommand<Playlist>(*playlist, before, after));
+	session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
 	commit_reversible_command ();
 }
 
@@ -412,7 +412,7 @@ Editor::nudge_forward (bool next)
                         XMLNode &before = r.playlist()->get_state();
 			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 MementoCommand<Playlist>(*(r.playlist()), &before, &after));
 		}
 
 		commit_reversible_command ();
@@ -452,7 +452,7 @@ Editor::nudge_backward (bool next)
 				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 MementoCommand<Playlist>(*(r.playlist()), &before, &after));
 		}
 
 		commit_reversible_command ();
@@ -488,7 +488,7 @@ Editor::nudge_forward_capture_offset ()
 			XMLNode &before = r.playlist()->get_state();
 			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 MementoCommand<Playlist>(*(r.playlist()), &before, &after));
 		}
 
 		commit_reversible_command ();
@@ -520,7 +520,7 @@ Editor::nudge_backward_capture_offset ()
 				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 MementoCommand<Playlist>(*(r.playlist()), &before, &after));
 		}
 
 		commit_reversible_command ();
@@ -1300,7 +1300,7 @@ Editor::add_location_from_selection ()
         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->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 }
 
@@ -1314,7 +1314,7 @@ Editor::add_location_from_playhead_cursor ()
         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->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 }
 
@@ -1333,7 +1333,7 @@ Editor::add_location_from_audio_region ()
         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->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 }
 
@@ -1752,7 +1752,7 @@ Editor::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->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 		session->commit_reversible_command ();
 	}
 }
@@ -1773,7 +1773,7 @@ Editor::clear_ranges ()
 		if (punchloc) session->locations()->add (punchloc);
 		
                 XMLNode &after = session->locations()->get_state();
-		session->add_command(new MementoCommand<Locations>(*(session->locations()), before, after));
+		session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 		session->commit_reversible_command ();
 	}
 }
@@ -1785,7 +1785,7 @@ Editor::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->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 	session->locations()->clear ();
 }
@@ -1835,7 +1835,7 @@ Editor::insert_region_list_drag (AudioRegion& region, int x, int y)
 	begin_reversible_command (_("insert dragged region"));
         XMLNode &before = playlist->get_state();
 	playlist->add_region (*(new AudioRegion (region)), where, 1.0);
-	session->add_command(new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+	session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 	commit_reversible_command ();
 }
 
@@ -1871,7 +1871,7 @@ Editor::insert_region_list_selection (float times)
 	begin_reversible_command (_("insert region"));
         XMLNode &before = playlist->get_state();
 	playlist->add_region (*(createRegion (*region)), edit_cursor->current_frame, times);
-	session->add_command(new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+	session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 	commit_reversible_command ();
 }
 
@@ -2311,7 +2311,7 @@ Editor::separate_region_from_selection ()
 					}
 
 					if (doing_undo) 
-                                            session->add_command(new MementoCommand<Playlist>(*playlist, *before, playlist->get_state()));
+                                            session->add_command(new MementoCommand<Playlist>(*playlist, before, &playlist->get_state()));
 				}
 			}
 		}
@@ -2364,7 +2364,7 @@ Editor::separate_regions_using_location (Location& loc)
 
 					playlist->partition ((jack_nframes_t)(loc.start() * speed), (jack_nframes_t)(loc.end() * speed), true);
 					if (doing_undo) 
-                                            session->add_command(new MementoCommand<Playlist>(*playlist, *before, playlist->get_state()));
+                                            session->add_command(new MementoCommand<Playlist>(*playlist, before, &playlist->get_state()));
 				}
 			}
 		}
@@ -2435,7 +2435,7 @@ Editor::crop_region_to_selection ()
                         XMLNode &before = (*i)->get_state();
 			region->trim_to (start, cnt, this);
                         XMLNode &after = (*i)->get_state();
-			session->add_command (new MementoCommand<Playlist>(*(*i), before, after));
+			session->add_command (new MementoCommand<Playlist>(*(*i), &before, &after));
 		}
 
 		commit_reversible_command ();
@@ -2477,7 +2477,7 @@ Editor::region_fill_track ()
 
 		XMLNode &before = pl->get_state();
 		pl->add_region (*(new AudioRegion (*ar)), ar->last_frame(), times);
-		session->add_command (new MementoCommand<Playlist>(*pl, before, pl->get_state()));
+		session->add_command (new MementoCommand<Playlist>(*pl, &before, &pl->get_state()));
 	}
 
 	commit_reversible_command ();
@@ -2527,7 +2527,7 @@ Editor::region_fill_selection ()
 		
                 XMLNode &before = playlist->get_state();
 		playlist->add_region (*(createRegion (*region)), start, times);
-		session->add_command (new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+		session->add_command (new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 	}
 	
 	commit_reversible_command ();			
@@ -2545,7 +2545,7 @@ Editor::set_a_regions_sync_position (Region& region, jack_nframes_t position)
         XMLNode &before = region.playlist()->get_state();
 	region.set_sync_position (position);
         XMLNode &after = region.playlist()->get_state();
-	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 	commit_reversible_command ();
 }
 
@@ -2566,7 +2566,7 @@ Editor::set_region_sync_from_edit_cursor ()
         XMLNode &before = region.playlist()->get_state();
 	region.set_sync_position (edit_cursor->current_frame);
         XMLNode &after = region.playlist()->get_state();
-	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 	commit_reversible_command ();
 }
 
@@ -2579,7 +2579,7 @@ Editor::remove_region_sync ()
                 XMLNode &before = region.playlist()->get_state();
 		region.clear_sync_position ();
                 XMLNode &after = region.playlist()->get_state();
-		session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+		session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 		commit_reversible_command ();
 	}
 }
@@ -2595,7 +2595,7 @@ Editor::naturalize ()
                 XMLNode &before = (*i)->region().get_state();
 		(*i)->region().move_to_natural_position (this);
                 XMLNode &after = (*i)->region().get_state();
-		session->add_command (new MementoCommand<Region>((*i)->region(), before, after));
+		session->add_command (new MementoCommand<Region>((*i)->region(), &before, &after));
 	}
 	commit_reversible_command ();
 }
@@ -2670,7 +2670,7 @@ Editor::align_selection_relative (RegionPoint point, jack_nframes_t position)
 		}
 
                 XMLNode &after = region.playlist()->get_state();
-		session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+		session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 
 	}
 
@@ -2723,7 +2723,7 @@ Editor::align_region_internal (Region& region, RegionPoint point, jack_nframes_t
 	}
 
 	XMLNode &after = region.playlist()->get_state();
-	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 }	
 
 void
@@ -2748,7 +2748,7 @@ Editor::trim_region_to_edit_cursor ()
         XMLNode &before = region.playlist()->get_state();
 	region.trim_end( session_frame_to_track_frame(edit_cursor->current_frame, speed), this);
         XMLNode &after = region.playlist()->get_state();
-	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 	commit_reversible_command ();
 }
 
@@ -2774,7 +2774,7 @@ Editor::trim_region_from_edit_cursor ()
         XMLNode &before = region.playlist()->get_state();
 	region.trim_front ( session_frame_to_track_frame(edit_cursor->current_frame, speed), this);
         XMLNode &after = region.playlist()->get_state();
-	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), before, after));
+	session->add_command(new MementoCommand<Playlist>(*(region.playlist()), &before, &after));
 	commit_reversible_command ();
 }
 
@@ -2889,7 +2889,7 @@ Editor::bounce_range_selection ()
                 XMLNode &before = playlist->get_state();
 		atv->audio_track()->bounce_range (start, cnt, itt);
                 XMLNode &after = playlist->get_state();
-		session->add_command (new MementoCommand<Playlist> (*playlist, before, after));
+		session->add_command (new MementoCommand<Playlist> (*playlist, &before, &after));
 	}
 	
 	commit_reversible_command ();
@@ -3007,7 +3007,7 @@ Editor::cut_copy_regions (CutCopyOp op)
 				insert_result = freezelist.insert (pl);
 				if (insert_result.second) {
 					pl->freeze ();
-                                        session->add_command (new MementoUndoCommand<Playlist>(*pl, pl->get_state()));
+                                        session->add_command (new MementoCommand<Playlist>(*pl, &pl->get_state(), 0));
 				}
 			}
 		}
@@ -3071,7 +3071,7 @@ Editor::cut_copy_regions (CutCopyOp op)
 	
 	for (set<Playlist*>::iterator pl = freezelist.begin(); pl != freezelist.end(); ++pl) {
 		(*pl)->thaw ();
-		session->add_command (new MementoRedoCommand<Playlist>(*(*pl), (*pl)->get_state()));
+		session->add_command (new MementoCommand<Playlist>(*(*pl), 0, &(*pl)->get_state()));
 	}
 }
 
@@ -3186,7 +3186,7 @@ Editor::paste_named_selection (float times)
 
                 XMLNode &before = apl->get_state();
 		apl->paste (**chunk, edit_cursor->current_frame, times);
-		session->add_command(new MementoCommand<AudioPlaylist>(*apl, before, apl->get_state()));
+		session->add_command(new MementoCommand<AudioPlaylist>(*apl, &before, &apl->get_state()));
 
 		if (tmp != ns->playlists.end()) {
 			chunk = tmp;
@@ -3217,7 +3217,7 @@ Editor::duplicate_some_regions (RegionSelection& regions, float times)
  		playlist = (*i)->region().playlist();
                 XMLNode &before = playlist->get_state();
 		playlist->duplicate (r, r.last_frame(), times);
-		session->add_command(new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+		session->add_command(new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 
 		c.disconnect ();
 
@@ -3258,7 +3258,7 @@ Editor::duplicate_selection (float times)
                 XMLNode &before = playlist->get_state();
 		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 MementoCommand<Playlist>(*playlist, &before, &after));
 
 		++ri;
 		if (ri == new_regions.end()) {
@@ -3309,7 +3309,7 @@ Editor::clear_playlist (Playlist& playlist)
         XMLNode &before = playlist.get_state();
 	playlist.clear ();
         XMLNode &after = playlist.get_state();
-	session->add_command (new MementoCommand<Playlist>(playlist, before, after));
+	session->add_command (new MementoCommand<Playlist>(playlist, &before, &after));
 	commit_reversible_command ();
 }
 
@@ -3346,7 +3346,7 @@ Editor::nudge_track (bool use_edit_cursor, bool forwards)
                 XMLNode &before = playlist->get_state();
 		playlist->nudge_after (start, distance, forwards);
                 XMLNode &after = playlist->get_state();
-		session->add_command (new MementoCommand<Playlist>(*playlist, before, after));
+		session->add_command (new MementoCommand<Playlist>(*playlist, &before, &after));
 	}
 	
 	commit_reversible_command ();			
@@ -3402,7 +3402,7 @@ Editor::normalize_region ()
 			continue;
  		XMLNode &before = arv->region().get_state();
 		arv->audio_region().normalize_to (0.0f);
-		session->add_command (new MementoCommand<Region>(arv->region(), before, arv->region().get_state()));
+		session->add_command (new MementoCommand<Region>(arv->region(), &before, &arv->region().get_state()));
 	}
 
 	commit_reversible_command ();
@@ -3429,7 +3429,7 @@ Editor::denormalize_region ()
 			continue;
 		XMLNode &before = arv->region().get_state();
 		arv->audio_region().set_scale_amplitude (1.0f);
-		session->add_command (new MementoCommand<Region>(arv->region(), before, arv->region().get_state()));
+		session->add_command (new MementoCommand<Region>(arv->region(), &before, &arv->region().get_state()));
 	}
 
 	commit_reversible_command ();
@@ -3476,7 +3476,7 @@ Editor::apply_filter (AudioFilter& filter, string command)
                         XMLNode &before = playlist->get_state();
 			playlist->replace_region (arv->region(), *(filter.results.front()), arv->region().position());
                         XMLNode &after = playlist->get_state();
-			session->add_command(new MementoCommand<Playlist>(*playlist, before, after));
+			session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
 		} else {
 			goto out;
 		}
diff --git a/gtk2_ardour/editor_route_list.cc b/gtk2_ardour/editor_route_list.cc
index bb38953038..512e2ecef1 100644
--- a/gtk2_ardour/editor_route_list.cc
+++ b/gtk2_ardour/editor_route_list.cc
@@ -30,6 +30,8 @@
 #include "mixer_strip.h"
 #include "gui_thread.h"
 
+#include <pbd/unknown_type.h>
+
 #include <ardour/route.h>
 
 #include "i18n.h"
@@ -41,79 +43,81 @@ using namespace Gtk;
 
 
 void
-Editor::handle_new_route (boost::shared_ptr<Route> route)
+Editor::handle_new_route (Session::RouteList& routes)
 {
-	ENSURE_GUI_THREAD(bind (mem_fun(*this, &Editor::handle_new_route), route));
-
+	ENSURE_GUI_THREAD(bind (mem_fun(*this, &Editor::handle_new_route), routes));
+	
 	TimeAxisView *tv;
+	RouteTimeAxisView *rtv;
 	TreeModel::Row parent;
 	TreeModel::Row row;
 
-	if (route->hidden()) {
-		return;
-	}
+	for (Session::RouteList::iterator x = routes.begin(); x != routes.end(); ++x) {
+		boost::shared_ptr<Route> route = (*x);
 
-	// FIXME
-	DataType type = route->default_type();
-	assert(type == ARDOUR::DataType::AUDIO || type == ARDOUR::DataType::MIDI);
-	
-	if (type == ARDOUR::DataType::AUDIO)
-		tv = new AudioTimeAxisView (*this, *session, route, track_canvas);
-	else
-		tv = new MidiTimeAxisView (*this, *session, route, track_canvas);
-	
+		if (route->hidden()) {
+			return;
+		}
+		
+		if (route->default_type() == ARDOUR::DataType::AUDIO)
+			tv = new AudioTimeAxisView (*this, *session, route, track_canvas);
+		else if (route->default_type() == ARDOUR::DataType::MIDI)
+			tv = new MidiTimeAxisView (*this, *session, route, track_canvas);
+		else
+			throw unknown_type();
+		
 #if 0
-	if (route_display_model->children().size() == 0) {
+		if (route_display_model->children().size() == 0) {
+			
+			/* set up basic entries */
+			
+			TreeModel::Row row;
+			
+			row = *(route_display_model->append());  // path = "0"
+			row[route_display_columns.text] = _("Busses");
+			row[route_display_columns.tv] = 0;
+			row = *(route_display_model->append());  // path = "1"
+			row[route_display_columns.text] = _("Tracks");
+			row[route_display_columns.tv] = 0;
+			
+		}
 		
-                /* set up basic entries */
-
-		TreeModel::Row row;
+		if (dynamic_cast<AudioTrack*>(route.get()) != 0) {
+			TreeModel::iterator iter = route_display_model->get_iter ("1");  // audio tracks 
+			parent = *iter;
+		} else {
+			TreeModel::iterator iter = route_display_model->get_iter ("0");  // busses
+			parent = *iter;
+		}
 		
-		row = *(route_display_model->append());  // path = "0"
-		row[route_display_columns.text] = _("Busses");
-		row[route_display_columns.tv] = 0;
-		row = *(route_display_model->append());  // path = "1"
-		row[route_display_columns.text] = _("Tracks");
-		row[route_display_columns.tv] = 0;
-
-	}
-
-	if (dynamic_cast<AudioTrack*>(route.get()) != 0) {
-		TreeModel::iterator iter = route_display_model->get_iter ("1");  // audio tracks 
-		parent = *iter;
-	} else {
-		TreeModel::iterator iter = route_display_model->get_iter ("0");  // busses
-		parent = *iter;
-	}
-	
-
-	row = *(route_display_model->append (parent.children()));
+		
+		row = *(route_display_model->append (parent.children()));
 #else 
-	row = *(route_display_model->append ());
+		row = *(route_display_model->append ());
 #endif
-
-	row[route_display_columns.text] = route->name();
-	row[route_display_columns.visible] = tv->marked_for_display();
-	row[route_display_columns.tv] = tv;
-	
-	track_views.push_back (tv);
-
-	ignore_route_list_reorder = true;
-	
-	RouteTimeAxisView* rtv = NULL;
-	if ((rtv = dynamic_cast<RouteTimeAxisView*> (tv)) != 0) {
-		/* added a new fresh one at the end */
-		if (rtv->route()->order_key(N_("editor")) == -1) {
-		        rtv->route()->set_order_key (N_("editor"), route_display_model->children().size()-1);
+		
+		row[route_display_columns.text] = route->name();
+		row[route_display_columns.visible] = tv->marked_for_display();
+		row[route_display_columns.tv] = tv;
+		
+		track_views.push_back (tv);
+		
+		ignore_route_list_reorder = true;
+		
+		if ((rtv = dynamic_cast<RouteTimeAxisView*> (tv)) != 0) {
+			/* added a new fresh one at the end */
+			if (rtv->route()->order_key(N_("editor")) == -1) {
+				rtv->route()->set_order_key (N_("editor"), route_display_model->children().size()-1);
+			}
 		}
+		
+		ignore_route_list_reorder = false;
+		
+		route->gui_changed.connect (mem_fun(*this, &Editor::handle_gui_changes));
+		
+		tv->GoingAway.connect (bind (mem_fun(*this, &Editor::remove_route), tv));
 	}
 
-	ignore_route_list_reorder = false;
-	
-	route->gui_changed.connect (mem_fun(*this, &Editor::handle_gui_changes));
-
-	tv->GoingAway.connect (bind (mem_fun(*this, &Editor::remove_route), tv));
-	
 	editor_mixer_button.set_sensitive(true);
 }
 
@@ -190,9 +194,9 @@ Editor::hide_track_in_display (TimeAxisView& tv)
 		}
 	}
 
-	AudioTimeAxisView* atv = dynamic_cast<AudioTimeAxisView*> (&tv);
+	RouteTimeAxisView* rtv = dynamic_cast<RouteTimeAxisView*> (&tv);
 
-	if (atv && current_mixer_strip && (atv->route() == current_mixer_strip->route())) {
+	if (rtv && current_mixer_strip && (rtv->route() == current_mixer_strip->route())) {
 		// this will hide the mixer strip
 		set_selected_mixer_strip (tv);
 	}
@@ -234,7 +238,7 @@ Editor::redisplay_route_list ()
 
 	for (n = 0, order = 0, position = 0, i = rows.begin(); i != rows.end(); ++i) {
 		TimeAxisView *tv = (*i)[route_display_columns.tv];
-		AudioTimeAxisView* at; 
+		RouteTimeAxisView* rt; 
 
 		if (tv == 0) {
 			// just a "title" row
@@ -247,8 +251,8 @@ Editor::redisplay_route_list ()
 			   to tracks.
 			*/
 			
-			if ((at = dynamic_cast<AudioTimeAxisView*> (tv)) != 0) {
-				at->route()->set_order_key (N_("editor"), order);
+			if ((rt = dynamic_cast<RouteTimeAxisView*> (tv)) != 0) {
+				rt->route()->set_order_key (N_("editor"), order);
 				++order;
 			}
 		}
@@ -500,9 +504,7 @@ Editor::initial_route_list_display ()
 
 	route_display_model->clear ();
 
-	for (Session::RouteList::iterator i = r.begin(); i != r.end(); ++i) {
-		handle_new_route (*i);
-	}
+	handle_new_route (r);
 
 	no_route_list_redisplay = false;
 
diff --git a/gtk2_ardour/editor_tempodisplay.cc b/gtk2_ardour/editor_tempodisplay.cc
index ff99c76351..e5b1a67cf3 100644
--- a/gtk2_ardour/editor_tempodisplay.cc
+++ b/gtk2_ardour/editor_tempodisplay.cc
@@ -278,7 +278,7 @@ Editor::mouse_add_new_tempo_event (jack_nframes_t frame)
         XMLNode &before = map.get_state();
 	map.add_tempo (Tempo (bpm), requested);
         XMLNode &after = map.get_state();
-	session->add_command(new MementoCommand<TempoMap>(map, before, after));
+	session->add_command(new MementoCommand<TempoMap>(map, &before, &after));
 	commit_reversible_command ();
 	
 	map.dump (cerr);
@@ -318,7 +318,7 @@ Editor::mouse_add_new_meter_event (jack_nframes_t frame)
 	begin_reversible_command (_("add meter mark"));
         XMLNode &before = map.get_state();
 	map.add_meter (Meter (bpb, note_type), requested);
-	session->add_command(new MementoCommand<TempoMap>(map, before, map.get_state()));
+	session->add_command(new MementoCommand<TempoMap>(map, &before, &map.get_state()));
 	commit_reversible_command ();
 	
 	map.dump (cerr);
@@ -370,7 +370,7 @@ Editor::edit_meter_section (MeterSection* section)
         XMLNode &before = session->tempo_map().get_state();
 	session->tempo_map().replace_meter (*section, Meter (bpb, note_type));
         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 ();
 }
 
@@ -400,7 +400,7 @@ Editor::edit_tempo_section (TempoSection* section)
 	session->tempo_map().replace_tempo (*section, Tempo (bpm));
 	session->tempo_map().move_tempo (*section, when);
         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 ();
 }
 
@@ -449,7 +449,7 @@ Editor::real_remove_tempo_marker (TempoSection *section)
 	XMLNode &before = session->tempo_map().get_state();
 	session->tempo_map().remove_tempo (*section);
 	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 ();
 
 	return FALSE;
@@ -483,7 +483,7 @@ Editor::real_remove_meter_marker (MeterSection *section)
 	XMLNode &before = session->tempo_map().get_state();
 	session->tempo_map().remove_meter (*section);
 	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 ();
 	return FALSE;
 }
diff --git a/gtk2_ardour/editor_timefx.cc b/gtk2_ardour/editor_timefx.cc
index 3fe0023d07..caa9698b8c 100644
--- a/gtk2_ardour/editor_timefx.cc
+++ b/gtk2_ardour/editor_timefx.cc
@@ -188,7 +188,7 @@ Editor::do_timestretch (TimeStretchDialog& dialog)
 			continue;
 		}
 	
-		if ((playlist = t->diskstream().playlist()) == 0) {
+		if ((playlist = t->diskstream()->playlist()) == 0) {
 			i = tmp;
 			continue;
 		}
@@ -210,7 +210,7 @@ Editor::do_timestretch (TimeStretchDialog& dialog)
 		XMLNode &before = playlist->get_state();
 		playlist->replace_region (region, *new_region, region.position());
 		XMLNode &after = playlist->get_state();
-		session->add_command (new MementoCommand<Playlist>(*playlist, before, after));
+		session->add_command (new MementoCommand<Playlist>(*playlist, &before, &after));
 
 		i = tmp;
 	}
diff --git a/gtk2_ardour/gain_automation_time_axis.cc b/gtk2_ardour/gain_automation_time_axis.cc
index c86c1390f3..47657e3292 100644
--- a/gtk2_ardour/gain_automation_time_axis.cc
+++ b/gtk2_ardour/gain_automation_time_axis.cc
@@ -67,7 +67,7 @@ GainAutomationTimeAxisView::add_automation_event (ArdourCanvas::Item* item, GdkE
         XMLNode &before = curve.get_state();
 	curve.add (when, y);
         XMLNode &after = curve.get_state();
-        _session.add_command(new MementoCommand<ARDOUR::Curve>(curve, before, after));
+        _session.add_command(new MementoCommand<ARDOUR::Curve>(curve, &before, &after));
 	_session.commit_reversible_command ();
 	_session.set_dirty ();
 }
diff --git a/gtk2_ardour/location_ui.cc b/gtk2_ardour/location_ui.cc
index deb4c1da36..12e7079de2 100644
--- a/gtk2_ardour/location_ui.cc
+++ b/gtk2_ardour/location_ui.cc
@@ -658,7 +658,7 @@ gint LocationUI::do_location_remove (ARDOUR::Location *loc)
 	XMLNode &before = session->locations()->get_state();
 	session->locations()->remove (loc);
 	XMLNode &after = session->locations()->get_state();
-	session->add_command(new MementoCommand<Locations>(*(session->locations()), before, after));
+	session->add_command(new MementoCommand<Locations>(*(session->locations()), &before, &after));
 	session->commit_reversible_command ();
 
 	return FALSE;
@@ -777,7 +777,7 @@ LocationUI::add_new_location()
 		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->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 		session->commit_reversible_command ();
 	}
 	
@@ -794,7 +794,7 @@ LocationUI::add_new_range()
 		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->add_command (new MementoCommand<Locations>(*(session->locations()), &before, &after));
 		session->commit_reversible_command ();
 	}
 }
diff --git a/gtk2_ardour/midi_streamview.cc b/gtk2_ardour/midi_streamview.cc
index f422005a5d..47148446eb 100644
--- a/gtk2_ardour/midi_streamview.cc
+++ b/gtk2_ardour/midi_streamview.cc
@@ -163,7 +163,8 @@ MidiStreamView::setup_rec_box ()
 
 				MidiRegion::SourceList sources;
 
-				MidiDiskstream* mds = dynamic_cast<MidiDiskstream*>(_trackview.get_diskstream());
+				// FIXME
+				boost::shared_ptr<MidiDiskstream> mds = boost::dynamic_pointer_cast<MidiDiskstream>(_trackview.get_diskstream());
 				assert(mds);
 
 				sources.push_back((Source*)mds->write_source());
@@ -189,8 +190,8 @@ MidiStreamView::setup_rec_box ()
 			/* start a new rec box */
 
 			MidiTrack* mt = _trackview.midi_track(); /* we know what it is already */
-			MidiDiskstream& ds = mt->midi_diskstream();
-			jack_nframes_t frame_pos = ds.current_capture_start ();
+			boost::shared_ptr<MidiDiskstream> ds = mt->midi_diskstream();
+			jack_nframes_t frame_pos = ds->current_capture_start ();
 			gdouble xstart = _trackview.editor.frame_to_pixel (frame_pos);
 			gdouble xend;
 			uint32_t fill_color;
diff --git a/gtk2_ardour/mixer_ui.cc b/gtk2_ardour/mixer_ui.cc
index c2eb588b2f..84fade5472 100644
--- a/gtk2_ardour/mixer_ui.cc
+++ b/gtk2_ardour/mixer_ui.cc
@@ -251,38 +251,42 @@ Mixer_UI::show_window ()
 }
 
 void
-Mixer_UI::add_strip (boost::shared_ptr<Route> route)
+Mixer_UI::add_strip (Session::RouteList& routes)
 {
-	ENSURE_GUI_THREAD(bind (mem_fun(*this, &Mixer_UI::add_strip), route));
+	ENSURE_GUI_THREAD(bind (mem_fun(*this, &Mixer_UI::add_strip), routes));
 	
 	MixerStrip* strip;
 
-	if (route->hidden()) {
-		return;
-	}
-
-	strip = new MixerStrip (*this, *session, route);
-	strips.push_back (strip);
-
-	strip->set_width (_strip_width);
-	show_strip (strip);
-
-	no_track_list_redisplay = true;
-
-	TreeModel::Row row = *(track_model->append());
-	row[track_columns.text] = route->name();
-
-	row[track_columns.visible] = true;
-	row[track_columns.route] = route;
-	row[track_columns.strip] = strip;
-
-	no_track_list_redisplay = false;
-	redisplay_track_list ();
-
-	route->name_changed.connect (bind (mem_fun(*this, &Mixer_UI::strip_name_changed), strip));
-	strip->GoingAway.connect (bind (mem_fun(*this, &Mixer_UI::remove_strip), strip));
+	for (Session::RouteList::iterator x = routes.begin(); x != routes.end(); ++x) {
+		boost::shared_ptr<Route> route = (*x);
 
-	strip->signal_button_release_event().connect (bind (mem_fun(*this, &Mixer_UI::strip_button_release_event), strip));
+		if (route->hidden()) {
+			return;
+		}
+		
+		strip = new MixerStrip (*this, *session, route);
+		strips.push_back (strip);
+		
+		strip->set_width (_strip_width);
+		show_strip (strip);
+		
+		no_track_list_redisplay = true;
+		
+		TreeModel::Row row = *(track_model->append());
+		row[track_columns.text] = route->name();
+		
+		row[track_columns.visible] = true;
+		row[track_columns.route] = route;
+		row[track_columns.strip] = strip;
+		
+		no_track_list_redisplay = false;
+		redisplay_track_list ();
+		
+		route->name_changed.connect (bind (mem_fun(*this, &Mixer_UI::strip_name_changed), strip));
+		strip->GoingAway.connect (bind (mem_fun(*this, &Mixer_UI::remove_strip), strip));
+		
+		strip->signal_button_release_event().connect (bind (mem_fun(*this, &Mixer_UI::strip_button_release_event), strip));
+	}
 }
 
 void
@@ -623,9 +627,7 @@ Mixer_UI::initial_track_display ()
 
 	track_model->clear ();
 
-	for (Session::RouteList::iterator i = copy.begin(); i != copy.end(); ++i) {
-		add_strip (*i);
-	}
+	add_strip (copy);
 
 	no_track_list_redisplay = false;
 
diff --git a/gtk2_ardour/mixer_ui.h b/gtk2_ardour/mixer_ui.h
index 6fe4120427..77021dc8fe 100644
--- a/gtk2_ardour/mixer_ui.h
+++ b/gtk2_ardour/mixer_ui.h
@@ -111,7 +111,7 @@ class Mixer_UI : public Gtk::Window
 
 	bool strip_scroller_button_release (GdkEventButton*);
 
-	void add_strip (boost::shared_ptr<ARDOUR::Route>);
+	void add_strip (ARDOUR::Session::RouteList&);
 	void remove_strip (MixerStrip *);
 
 	void hide_all_strips (bool with_select);
diff --git a/gtk2_ardour/pan_automation_time_axis.cc b/gtk2_ardour/pan_automation_time_axis.cc
index ec884151b5..bbd4b3b06c 100644
--- a/gtk2_ardour/pan_automation_time_axis.cc
+++ b/gtk2_ardour/pan_automation_time_axis.cc
@@ -92,7 +92,7 @@ PanAutomationTimeAxisView::add_automation_event (ArdourCanvas::Item* item, GdkEv
 	XMLNode &before = alist.get_state();
 	alist.add (when, y);
 	XMLNode &after = alist.get_state();
-        _session.add_command(new MementoCommand<AutomationList>(alist, before, after));
+        _session.add_command(new MementoCommand<AutomationList>(alist, &before, &after));
 	_session.commit_reversible_command ();
 	_session.set_dirty ();
 }
diff --git a/gtk2_ardour/playlist_selector.cc b/gtk2_ardour/playlist_selector.cc
index 8eaac7cb9d..68227d193c 100644
--- a/gtk2_ardour/playlist_selector.cc
+++ b/gtk2_ardour/playlist_selector.cc
@@ -90,7 +90,7 @@ void
 PlaylistSelector::show_for (RouteUI* ruix)
 {
 	vector<const char*> item;
-	Diskstream* this_ds;
+	boost::shared_ptr<Diskstream> this_ds;
 	string str;
 
 	rui = ruix;
@@ -116,7 +116,7 @@ PlaylistSelector::show_for (RouteUI* ruix)
 	
 	for (DSPL_Map::iterator x = dspl_map.begin(); x != dspl_map.end(); ++x) {
 
-		Diskstream* ds = session->diskstream_by_id (x->first);
+		boost::shared_ptr<Diskstream> ds = session->diskstream_by_id (x->first);
 
 		if (ds == 0) {
 			continue;
@@ -243,7 +243,7 @@ PlaylistSelector::selection_changed ()
 			return;
 		}
 		
-		at->diskstream().use_playlist (apl);
+		at->diskstream()->use_playlist (apl);
 
 		hide ();
 	}
diff --git a/gtk2_ardour/redirect_automation_time_axis.cc b/gtk2_ardour/redirect_automation_time_axis.cc
index e527fd1d5e..f1e8eae9eb 100644
--- a/gtk2_ardour/redirect_automation_time_axis.cc
+++ b/gtk2_ardour/redirect_automation_time_axis.cc
@@ -102,7 +102,7 @@ RedirectAutomationTimeAxisView::add_automation_event (ArdourCanvas::Item* item,
                 XMLNode &before = alist.get_state();
 		alist.add (when, y);
                 XMLNode &after = alist.get_state();
-                _session.add_command(new MementoCommand<AutomationList>(alist, before, after));
+                _session.add_command(new MementoCommand<AutomationList>(alist, &before, &after));
 		_session.commit_reversible_command ();
 		_session.set_dirty ();
 	}
diff --git a/gtk2_ardour/region_gain_line.cc b/gtk2_ardour/region_gain_line.cc
index 0a4a3d29ea..e2b1d6c826 100644
--- a/gtk2_ardour/region_gain_line.cc
+++ b/gtk2_ardour/region_gain_line.cc
@@ -48,7 +48,7 @@ AudioRegionGainLine::start_drag (ControlPoint* cp, float fraction)
 {
 	AutomationLine::start_drag(cp,fraction);
 	if (!rv.audio_region().envelope_active()) {
-                trackview.session().add_command(new MementoUndoCommand<AudioRegion>(rv.audio_region(), rv.audio_region().get_state()));
+                trackview.session().add_command(new MementoCommand<AudioRegion>(rv.audio_region(), &rv.audio_region().get_state(), 0));
                 rv.audio_region().set_envelope_active(false);
 	}
 }
@@ -68,12 +68,12 @@ AudioRegionGainLine::remove_point (ControlPoint& cp)
                 XMLNode &before = rv.audio_region().get_state();
 		rv.audio_region().set_envelope_active(true);
                 XMLNode &after = rv.audio_region().get_state();
-                trackview.session().add_command(new MementoCommand<AudioRegion>(rv.audio_region(), before, after));
+                trackview.session().add_command(new MementoCommand<AudioRegion>(rv.audio_region(), &before, &after));
 	}
 
 	alist.erase (mr.start, mr.end);
 
-	trackview.editor.current_session()->add_command (new MementoCommand<AudioRegionGainLine>(*this, before, get_state()));
+	trackview.editor.current_session()->add_command (new MementoCommand<AudioRegionGainLine>(*this, &before, &get_state()));
 	trackview.editor.current_session()->commit_reversible_command ();
 	trackview.editor.current_session()->set_dirty ();
 }
@@ -83,7 +83,7 @@ AudioRegionGainLine::end_drag (ControlPoint* cp)
 {
 	if (!rv.audio_region().envelope_active()) {
 		rv.audio_region().set_envelope_active(true);
-                trackview.session().add_command(new MementoRedoCommand<AudioRegion>(rv.audio_region(), rv.audio_region().get_state()));
+                trackview.session().add_command(new MementoCommand<AudioRegion>(rv.audio_region(), 0, &rv.audio_region().get_state()));
 	}
 	AutomationLine::end_drag(cp);
 }
diff --git a/gtk2_ardour/route_params_ui.cc b/gtk2_ardour/route_params_ui.cc
index 8d8efad8a2..c23ed272e1 100644
--- a/gtk2_ardour/route_params_ui.cc
+++ b/gtk2_ardour/route_params_ui.cc
@@ -159,22 +159,26 @@ RouteParams_UI::~RouteParams_UI ()
 }
 
 void
-RouteParams_UI::add_route (boost::shared_ptr<Route> route)
+RouteParams_UI::add_routes (Session::RouteList& routes)
 {
-	ENSURE_GUI_THREAD(bind (mem_fun(*this, &RouteParams_UI::add_route), route));
+	ENSURE_GUI_THREAD(bind (mem_fun(*this, &RouteParams_UI::add_routes), routes));
 	
-	if (route->hidden()) {
-		return;
-	}
-
-	TreeModel::Row row = *(route_display_model->append());
-	row[route_display_columns.text] = route->name();
-	row[route_display_columns.route] = route;
+	for (Session::RouteList::iterator x = routes.begin(); x != routes.end(); ++x) {
+		boost::shared_ptr<Route> route = (*x);
 
-	//route_select_list.rows().back().select ();
-	
-	route->name_changed.connect (bind (mem_fun(*this, &RouteParams_UI::route_name_changed), route));
-	route->GoingAway.connect (bind (mem_fun(*this, &RouteParams_UI::route_removed), route));
+		if (route->hidden()) {
+			return;
+		}
+		
+		TreeModel::Row row = *(route_display_model->append());
+		row[route_display_columns.text] = route->name();
+		row[route_display_columns.route] = route;
+		
+		//route_select_list.rows().back().select ();
+		
+		route->name_changed.connect (bind (mem_fun(*this, &RouteParams_UI::route_name_changed), route));
+		route->GoingAway.connect (bind (mem_fun(*this, &RouteParams_UI::route_removed), route));
+	}
 }
 
 
@@ -355,9 +359,10 @@ RouteParams_UI::set_session (Session *sess)
 	route_display_model->clear();
 
 	if (session) {
-		session->foreach_route (this, &RouteParams_UI::add_route);
+		boost::shared_ptr<Session::RouteList> r = session->get_routes();
+		add_routes (*r);
 		session->going_away.connect (mem_fun(*this, &ArdourDialog::session_gone));
-		session->RouteAdded.connect (mem_fun(*this, &RouteParams_UI::add_route));
+		session->RouteAdded.connect (mem_fun(*this, &RouteParams_UI::add_routes));
 		start_updating ();
 	} else {
 		stop_updating ();
diff --git a/gtk2_ardour/route_params_ui.h b/gtk2_ardour/route_params_ui.h
index 5f487d6e5c..eff31023f7 100644
--- a/gtk2_ardour/route_params_ui.h
+++ b/gtk2_ardour/route_params_ui.h
@@ -159,7 +159,7 @@ class RouteParams_UI : public ArdourDialog
 	Glib::RefPtr<Gtk::ListStore> route_display_model;
 
 	
-	void add_route (boost::shared_ptr<ARDOUR::Route>);
+	void add_routes (ARDOUR::Session::RouteList&);
 
 	void route_name_changed (void *src, boost::shared_ptr<ARDOUR::Route> route);
 	void route_removed (boost::shared_ptr<ARDOUR::Route> route);
diff --git a/gtk2_ardour/route_time_axis.cc b/gtk2_ardour/route_time_axis.cc
index e2e1fb2149..e7a6df2f27 100644
--- a/gtk2_ardour/route_time_axis.cc
+++ b/gtk2_ardour/route_time_axis.cc
@@ -728,7 +728,7 @@ RouteTimeAxisView::rename_current_playlist ()
 	ArdourPrompter prompter (true);
 	string name;
 
-	Diskstream *const ds = get_diskstream();
+	boost::shared_ptr<Diskstream> ds = get_diskstream();
 	if (!ds || ds->destructive())
 		return;
 
@@ -759,7 +759,7 @@ RouteTimeAxisView::use_copy_playlist (bool prompt)
 {
 	string name;
 	
-	Diskstream *const ds = get_diskstream();
+	boost::shared_ptr<Diskstream> ds = get_diskstream();
 	if (!ds || ds->destructive())
 		return;
 
@@ -800,7 +800,7 @@ RouteTimeAxisView::use_new_playlist (bool prompt)
 {
 	string name;
 	
-	Diskstream *const ds = get_diskstream();
+	boost::shared_ptr<Diskstream> ds = get_diskstream();
 	if (!ds || ds->destructive())
 		return;
 
@@ -838,7 +838,7 @@ RouteTimeAxisView::use_new_playlist (bool prompt)
 void
 RouteTimeAxisView::clear_playlist ()
 {
-	Diskstream *const ds = get_diskstream();
+	boost::shared_ptr<Diskstream> ds = get_diskstream();
 	if (!ds || ds->destructive())
 		return;
 
@@ -878,8 +878,7 @@ RouteTimeAxisView::selection_click (GdkEventButton* ev)
 
 	switch (Keyboard::selection_type (ev->state)) {
 	case Selection::Toggle:
-		/* XXX this is not right */
-		editor.get_selection().add (*tracks);
+		editor.get_selection().toggle (*tracks);
 		break;
 		
 	case Selection::Set:
@@ -964,7 +963,7 @@ RouteTimeAxisView::name() const
 Playlist *
 RouteTimeAxisView::playlist () const 
 {
-	Diskstream *ds;
+	boost::shared_ptr<Diskstream> ds;
 
 	if ((ds = get_diskstream()) != 0) {
 		return ds->playlist(); 
@@ -1014,7 +1013,7 @@ RouteTimeAxisView::hide_click ()
 Region*
 RouteTimeAxisView::find_next_region (jack_nframes_t pos, RegionPoint point, int32_t dir)
 {
-	Diskstream *stream;
+	boost::shared_ptr<Diskstream> stream;
 	Playlist *playlist;
 
 	if ((stream = get_diskstream()) != 0 && (playlist = stream->playlist()) != 0) {
@@ -1028,7 +1027,7 @@ bool
 RouteTimeAxisView::cut_copy_clear (Selection& selection, CutCopyOp op)
 {
 	Playlist* what_we_got;
-	Diskstream* ds = get_diskstream();
+	boost::shared_ptr<Diskstream> ds = get_diskstream();
 	Playlist* playlist;
 	bool ret = false;
 
@@ -1054,7 +1053,7 @@ RouteTimeAxisView::cut_copy_clear (Selection& selection, CutCopyOp op)
 	case Cut:
 		if ((what_we_got = playlist->cut (time)) != 0) {
 			editor.get_cut_buffer().add (what_we_got);
-			_session.add_command( new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+			_session.add_command( new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 			ret = true;
 		}
 		break;
@@ -1066,7 +1065,7 @@ RouteTimeAxisView::cut_copy_clear (Selection& selection, CutCopyOp op)
 
 	case Clear:
 		if ((what_we_got = playlist->cut (time)) != 0) {
-			_session.add_command( new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+			_session.add_command( new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 			what_we_got->unref ();
 			ret = true;
 		}
@@ -1097,7 +1096,7 @@ RouteTimeAxisView::paste (jack_nframes_t pos, float times, Selection& selection,
 	
 	XMLNode &before = playlist->get_state();
 	playlist->paste (**p, pos, times);
-	_session.add_command( new MementoCommand<Playlist>(*playlist, before, playlist->get_state()));
+	_session.add_command( new MementoCommand<Playlist>(*playlist, &before, &playlist->get_state()));
 
 	return true;
 }
diff --git a/gtk2_ardour/route_ui.cc b/gtk2_ardour/route_ui.cc
index 6b3c2a820c..3ede0bc1c7 100644
--- a/gtk2_ardour/route_ui.cc
+++ b/gtk2_ardour/route_ui.cc
@@ -76,7 +76,7 @@ RouteUI::RouteUI (boost::shared_ptr<ARDOUR::Route> rt, ARDOUR::Session& sess, co
 	if (is_track()) {
 		boost::shared_ptr<Track> t = boost::dynamic_pointer_cast<Track>(_route);
 
-		t->diskstream().RecordEnableChanged.connect (mem_fun (*this, &RouteUI::route_rec_enable_changed));
+		t->diskstream()->RecordEnableChanged.connect (mem_fun (*this, &RouteUI::route_rec_enable_changed));
 
 		_session.RecordStateChanged.connect (mem_fun (*this, &RouteUI::session_rec_enable_changed));
 
@@ -577,7 +577,7 @@ RouteUI::reversibly_apply_route_boolean (string name, void (Route::*func)(bool,
         XMLNode &before = _route->get_state();
         bind(mem_fun(*_route, func), yn, arg)();
         XMLNode &after = _route->get_state();
-        _session.add_command (new MementoCommand<Route>(*_route, before, after));
+        _session.add_command (new MementoCommand<Route>(*_route, &before, &after));
 	_session.commit_reversible_command ();
 }
 
@@ -588,7 +588,7 @@ RouteUI::reversibly_apply_audio_track_boolean (string name, void (AudioTrack::*f
         XMLNode &before = audio_track()->get_state();
 	bind (mem_fun (*audio_track(), func), yn, arg)();
         XMLNode &after = audio_track()->get_state();
-	_session.add_command (new MementoCommand<AudioTrack>(*audio_track(), before, after));
+	_session.add_command (new MementoCommand<AudioTrack>(*audio_track(), &before, &after));
 	_session.commit_reversible_command ();
 }
 
@@ -599,7 +599,7 @@ RouteUI::reversibly_apply_track_boolean (string name, void (Track::*func)(bool,
         XMLNode &before = track()->get_state();
 	bind (mem_fun (*track(), func), yn, arg)();
         XMLNode &after = track()->get_state();
-	_session.add_command (new MementoCommand<Track>(*track(), before, after));
+	_session.add_command (new MementoCommand<Track>(*track(), &before, &after));
 	_session.commit_reversible_command ();
 }
 
@@ -746,7 +746,6 @@ void
 RouteUI::route_removed ()
 {
 	ENSURE_GUI_THREAD(mem_fun (*this, &RouteUI::route_removed));
-	
 	delete this;
 }
 
@@ -930,15 +929,15 @@ RouteUI::midi_track() const
 	return dynamic_cast<MidiTrack*>(_route.get());
 }
 
-Diskstream*
+boost::shared_ptr<Diskstream>
 RouteUI::get_diskstream () const
 {
 	boost::shared_ptr<Track> t;
 
 	if ((t = boost::dynamic_pointer_cast<Track>(_route)) != 0) {
-		return &t->diskstream();
+		return t->diskstream();
 	} else {
-		return 0;
+		return boost::shared_ptr<Diskstream> ((Diskstream*) 0);
 	}
 }
 
diff --git a/gtk2_ardour/route_ui.h b/gtk2_ardour/route_ui.h
index 156063a8e5..b01d7d41cb 100644
--- a/gtk2_ardour/route_ui.h
+++ b/gtk2_ardour/route_ui.h
@@ -60,7 +60,7 @@ class RouteUI : public virtual AxisView
 	ARDOUR::AudioTrack* audio_track() const;
 	ARDOUR::MidiTrack*  midi_track() const;
 	
-	ARDOUR::Diskstream* get_diskstream() const;
+	boost::shared_ptr<ARDOUR::Diskstream> get_diskstream() const;
 
 	string name() const;
 
diff --git a/gtk2_ardour/selection.cc b/gtk2_ardour/selection.cc
index 086d878994..aa7fdbe30f 100644
--- a/gtk2_ardour/selection.cc
+++ b/gtk2_ardour/selection.cc
@@ -180,6 +180,14 @@ Selection::toggle (Playlist* pl)
 }
 
 void
+Selection::toggle (const list<TimeAxisView*>& track_list)
+{
+	for (list<TimeAxisView*>::const_iterator i = track_list.begin(); i != track_list.end(); ++i) {
+		toggle ( (*i) );
+	}
+}
+
+void
 Selection::toggle (TimeAxisView* track)
 {
 	TrackSelection::iterator i;
@@ -616,6 +624,7 @@ Selection::set (list<Selectable*>& selectables)
 	add (selectables);
 }
 
+
 void
 Selection::add (list<Selectable*>& selectables)
 {
diff --git a/gtk2_ardour/streamview.cc b/gtk2_ardour/streamview.cc
index 82f941f9bd..ff51ca4b9f 100644
--- a/gtk2_ardour/streamview.cc
+++ b/gtk2_ardour/streamview.cc
@@ -207,7 +207,7 @@ StreamView::undisplay_diskstream ()
 }
 
 void
-StreamView::display_diskstream (Diskstream *ds)
+StreamView::display_diskstream (boost::shared_ptr<Diskstream> ds)
 {
 	playlist_change_connection.disconnect();
 	playlist_changed (ds);
@@ -225,7 +225,7 @@ StreamView::playlist_modified ()
 }
 
 void
-StreamView::playlist_changed (Diskstream *ds)
+StreamView::playlist_changed (boost::shared_ptr<Diskstream> ds)
 {
 	ENSURE_GUI_THREAD (bind (mem_fun (*this, &StreamView::playlist_changed), ds));
 
@@ -264,9 +264,7 @@ StreamView::diskstream_changed ()
 	Track *t;
 
 	if ((t = _trackview.track()) != 0) {
-		Diskstream& ds = t->diskstream();
-		/* XXX grrr: when will SigC++ allow me to bind references? */
-		Gtkmm2ext::UI::instance()->call_slot (bind (mem_fun (*this, &StreamView::display_diskstream), &ds));
+		Gtkmm2ext::UI::instance()->call_slot (bind (mem_fun (*this, &StreamView::display_diskstream), t->diskstream()));
 	} else {
 		Gtkmm2ext::UI::instance()->call_slot (mem_fun (*this, &StreamView::undisplay_diskstream));
 	}
diff --git a/gtk2_ardour/streamview.h b/gtk2_ardour/streamview.h
index bee51e8835..fb49433cce 100644
--- a/gtk2_ardour/streamview.h
+++ b/gtk2_ardour/streamview.h
@@ -111,13 +111,13 @@ protected:
 	virtual void remove_region_view (ARDOUR::Region* );
 	void         remove_rec_region (ARDOUR::Region*);
 
-	void         display_diskstream (ARDOUR::Diskstream* );
+	void         display_diskstream (boost::shared_ptr<ARDOUR::Diskstream>);
 	virtual void undisplay_diskstream ();
 	virtual void redisplay_diskstream () = 0;
 	void         diskstream_changed ();
 	
 	void         playlist_state_changed (ARDOUR::Change);
-	virtual void playlist_changed (ARDOUR::Diskstream* );
+	virtual void playlist_changed (boost::shared_ptr<ARDOUR::Diskstream>);
 	virtual void playlist_modified ();
 	
 	virtual void color_handler (ColorID, uint32_t) = 0;