major changes to Region, AudioRegion, Playlist, AudioPlaylist and Crossfade state management, to try to fix undo/redo. Not finished, butthe speedups etc. are in place

git-svn-id: svn://localhost/ardour2/trunk@993 d708f5d6-7413-0410-9779-e7cbd77b26cf

22 files changed, 391 insertions, 944 deletions

diff --git a/gtk2_ardour/audio_streamview.cc b/gtk2_ardour/audio_streamview.cc
index 0a74d89d35..3cca792523 100644
--- a/gtk2_ardour/audio_streamview.cc
+++ b/gtk2_ardour/audio_streamview.cc
@@ -254,7 +254,7 @@ AudioStreamView::add_crossfade (Crossfade *crossfade)
 	/* first see if we already have a CrossfadeView for this Crossfade */
 
 	for (list<CrossfadeView *>::iterator i = crossfade_views.begin(); i != crossfade_views.end(); ++i) {
-		if (&(*i)->crossfade == crossfade) {
+		if ((*i)->crossfade == *crossfade) {
 			if (!crossfades_visible) {
 				(*i)->hide();
 			} else {
@@ -313,7 +313,6 @@ AudioStreamView::redisplay_diskstream ()
 	list<RegionView *>::iterator i, tmp;
 	list<CrossfadeView*>::iterator xi, tmpx;
 
-	
 	for (i = region_views.begin(); i != region_views.end(); ++i) {
 		(*i)->set_valid (false);
 	}
@@ -327,6 +326,7 @@ AudioStreamView::redisplay_diskstream ()
 
 	if (_trackview.is_audio_track()) {
 		_trackview.get_diskstream()->playlist()->foreach_region (static_cast<StreamView*>(this), &StreamView::add_region_view);
+
 		AudioPlaylist* apl = dynamic_cast<AudioPlaylist*>(_trackview.get_diskstream()->playlist());
 		if (apl)
 			apl->foreach_crossfade (this, &AudioStreamView::add_crossfade);
@@ -358,7 +358,9 @@ AudioStreamView::redisplay_diskstream ()
 
 	/* now fix layering */
 
-	playlist_modified ();
+	for (RegionViewList::iterator i = region_views.begin(); i != region_views.end(); ++i) {
+		region_layered (*i);
+	}
 }
 
 void
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 67f3acccf9..99e1f5bb1e 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -3074,9 +3074,6 @@ Editor::set_selected_regionview_from_click (bool press, Selection::Operation op,
 
 		switch (clicked_regionview->region()->coverage (first_frame, last_frame)) {
 		case OverlapNone:
-			cerr << "no overlap, first = " << first_frame << " last = " << last_frame << " region = " 
-			     << clicked_regionview->region()->first_frame() << " .. " << clicked_regionview->region()->last_frame() << endl;
-
 			if (last_frame < clicked_regionview->region()->first_frame()) {
 				first_frame = last_frame;
 				last_frame = clicked_regionview->region()->last_frame();
@@ -3087,9 +3084,6 @@ Editor::set_selected_regionview_from_click (bool press, Selection::Operation op,
 			break;
 
 		case OverlapExternal:
-			cerr << "external overlap, first = " << first_frame << " last = " << last_frame << " region = " 
-			     << clicked_regionview->region()->first_frame() << " .. " << clicked_regionview->region()->last_frame() << endl;
-
 			if (last_frame < clicked_regionview->region()->first_frame()) {
 				first_frame = last_frame;
 				last_frame = clicked_regionview->region()->last_frame();
@@ -3100,9 +3094,6 @@ Editor::set_selected_regionview_from_click (bool press, Selection::Operation op,
 			break;
 
 		case OverlapInternal:
-			cerr << "internal overlap, first = " << first_frame << " last = " << last_frame << " region = " 
-			     << clicked_regionview->region()->first_frame() << " .. " << clicked_regionview->region()->last_frame() << endl;
-
 			if (last_frame < clicked_regionview->region()->first_frame()) {
 				first_frame = last_frame;
 				last_frame = clicked_regionview->region()->last_frame();
diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index 0ee110bf30..45252e052c 100644
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -4837,7 +4837,7 @@ Editor::mouse_brush_insert_region (RegionView* rv, nframes_t pos)
 	
 	// playlist is frozen, so we have to update manually
 	
-	playlist->StateChanged (Change (~0)); /* EMIT SIGNAL */
+	playlist->Modified(); /* EMIT SIGNAL */
 }
 
 gint
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 0a3104d36a..280804c94f 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -2910,14 +2910,26 @@ Editor::cut_copy_points (CutCopyOp op)
 	}
 }
 
+struct PlaylistState {
+    Playlist* playlist;
+    XMLNode*  before;
+};
+
+struct lt_playlist {
+    bool operator () (const PlaylistState& a, const PlaylistState& b) {
+	    return a.playlist < b.playlist;
+    }
+};
+	
 void
 Editor::cut_copy_regions (CutCopyOp op)
 {
         typedef std::map<AudioPlaylist*,AudioPlaylist*> PlaylistMapping;
 	PlaylistMapping pmap;
 	nframes_t first_position = max_frames;
-	set<Playlist*> freezelist;
-	pair<set<Playlist*>::iterator,bool> insert_result;
+
+	set<PlaylistState, lt_playlist> freezelist;
+	pair<set<PlaylistState, lt_playlist>::iterator,bool> insert_result;
 
 	for (RegionSelection::iterator x = selection->regions.begin(); x != selection->regions.end(); ++x) {
 		first_position = min ((*x)->region()->position(), first_position);
@@ -2925,10 +2937,15 @@ Editor::cut_copy_regions (CutCopyOp op)
 		if (op == Cut || op == Clear) {
 			AudioPlaylist *pl = dynamic_cast<AudioPlaylist*>((*x)->region()->playlist());
 			if (pl) {
-				insert_result = freezelist.insert (pl);
+
+				PlaylistState before;
+				before.playlist = pl;
+				before.before = &pl->get_state();
+				
+				insert_result = freezelist.insert (before);
+
 				if (insert_result.second) {
 					pl->freeze ();
-                                        session->add_command (new MementoCommand<Playlist>(*pl, &pl->get_state(), 0));
 				}
 			}
 		}
@@ -2990,9 +3007,9 @@ Editor::cut_copy_regions (CutCopyOp op)
 		cut_buffer->set (foo);
 	}
 	
-	for (set<Playlist*>::iterator pl = freezelist.begin(); pl != freezelist.end(); ++pl) {
-		(*pl)->thaw ();
-		session->add_command (new MementoCommand<Playlist>(*(*pl), 0, &(*pl)->get_state()));
+	for (set<PlaylistState, lt_playlist>::iterator pl = freezelist.begin(); pl != freezelist.end(); ++pl) {
+		(*pl).playlist->thaw ();
+		session->add_command (new MementoCommand<Playlist>(*(*pl).playlist, (*pl).before, &(*pl).playlist->get_state()));
 	}
 }
 
diff --git a/gtk2_ardour/route_time_axis.cc b/gtk2_ardour/route_time_axis.cc
index e0d976c233..eb96791d28 100644
--- a/gtk2_ardour/route_time_axis.cc
+++ b/gtk2_ardour/route_time_axis.cc
@@ -244,9 +244,6 @@ RouteTimeAxisView::set_playlist (Playlist *newplaylist)
 	assert(pl);
 
 	modified_connection.disconnect ();
-	state_changed_connection.disconnect ();
-	
-	state_changed_connection = pl->StateChanged.connect (mem_fun(*this, &RouteTimeAxisView::playlist_state_changed));
 	modified_connection = pl->Modified.connect (mem_fun(*this, &RouteTimeAxisView::playlist_modified));
 }
 
diff --git a/gtk2_ardour/route_time_axis.h b/gtk2_ardour/route_time_axis.h
index 65d82506b8..1eb0cea00b 100644
--- a/gtk2_ardour/route_time_axis.h
+++ b/gtk2_ardour/route_time_axis.h
@@ -248,7 +248,6 @@ protected:
 	vector<RedirectAutomationLine*> redirect_automation_curves;
 
 	sigc::connection modified_connection;
-	sigc::connection state_changed_connection;
 };
 
 #endif /* __ardour_route_time_axis_h__ */
diff --git a/gtk2_ardour/streamview.cc b/gtk2_ardour/streamview.cc
index 10d409a9b0..75fb003d77 100644
--- a/gtk2_ardour/streamview.cc
+++ b/gtk2_ardour/streamview.cc
@@ -206,9 +206,7 @@ StreamView::playlist_modified ()
 {
 	ENSURE_GUI_THREAD (mem_fun (*this, &StreamView::playlist_modified));
 
-	for (RegionViewList::iterator i = region_views.begin(); i != region_views.end(); ++i) {
-		region_layered (*i);
-	}
+	redisplay_diskstream ();
 }
 
 void
@@ -231,21 +229,10 @@ StreamView::playlist_changed (boost::shared_ptr<Diskstream> ds)
 
 	/* catch changes */
 
-	playlist_connections.push_back (ds->playlist()->RegionAdded.connect (mem_fun (*this, &StreamView::add_region_view)));
-	playlist_connections.push_back (ds->playlist()->RegionRemoved.connect (mem_fun (*this, &StreamView::remove_region_view)));
-	playlist_connections.push_back (ds->playlist()->StateChanged.connect (mem_fun (*this, &StreamView::playlist_state_changed)));
 	playlist_connections.push_back (ds->playlist()->Modified.connect (mem_fun (*this, &StreamView::playlist_modified)));
 }
 
 void
-StreamView::playlist_state_changed (Change ignored)
-{
-	ENSURE_GUI_THREAD (bind (mem_fun (*this, &StreamView::playlist_state_changed), ignored));
-
-	redisplay_diskstream ();
-}
-
-void
 StreamView::diskstream_changed ()
 {
 	Track *t;
diff --git a/gtk2_ardour/streamview.h b/gtk2_ardour/streamview.h
index cc5f9cb414..657bfa9044 100644
--- a/gtk2_ardour/streamview.h
+++ b/gtk2_ardour/streamview.h
@@ -116,7 +116,6 @@ protected:
 	virtual void redisplay_diskstream () = 0;
 	void         diskstream_changed ();
 	
-	void         playlist_state_changed (ARDOUR::Change);
 	virtual void playlist_changed (boost::shared_ptr<ARDOUR::Diskstream>);
 	virtual void playlist_modified ();
 	
diff --git a/libs/ardour/ardour/audioplaylist.h b/libs/ardour/ardour/audioplaylist.h
index 341b08930c..6d67e0f793 100644
--- a/libs/ardour/ardour/audioplaylist.h
+++ b/libs/ardour/ardour/audioplaylist.h
@@ -38,19 +38,6 @@ class AudioPlaylist : public ARDOUR::Playlist
 {
   public:
 	typedef std::list<Crossfade*> Crossfades;
-
-  private:
-	
-	struct State : public ARDOUR::StateManager::State {
-	    RegionList regions;
-	    std::list<UndoAction> region_states;
-	    
-	    Crossfades crossfades;
-	    std::list<UndoAction> crossfade_states;
-	    
-	    State (std::string why) : ARDOUR::StateManager::State (why) {}
-	    ~State ();
-	};
 	
    public:
 	AudioPlaylist (Session&, const XMLNode&, bool hidden = false);
@@ -58,35 +45,21 @@ class AudioPlaylist : public ARDOUR::Playlist
 	AudioPlaylist (const AudioPlaylist&, string name, bool hidden = false);
 	AudioPlaylist (const AudioPlaylist&, nframes_t start, nframes_t cnt, string name, bool hidden = false);
 
-	void clear (bool with_save = true);
+	void clear ();
 
         nframes_t read (Sample *dst, Sample *mixdown, float *gain_buffer, nframes_t start, nframes_t cnt, uint32_t chan_n=0);
 
 	int set_state (const XMLNode&);
-	UndoAction get_memento() const;
 
 	sigc::signal<void,Crossfade *> NewCrossfade; 
 
 	template<class T> void foreach_crossfade (T *t, void (T::*func)(Crossfade *));
 	void crossfades_at (nframes_t frame, Crossfades&);
 
-	template<class T> void apply_to_history (T& obj, void (T::*method)(const ARDOUR::StateManager::StateMap&, state_id_t)) {
-		RegionLock rlock (this);
-		(obj.*method) (states, _current_state_id);
-	}
-
 	bool destroy_region (boost::shared_ptr<Region>);
 
-	void drop_all_states ();
-
     protected:
 
-	/* state management */
-
-	StateManager::State* state_factory (std::string) const;
-	Change restore_state (StateManager::State&);
-	void send_state_change (Change);
-
 	/* playlist "callbacks" */
 	void notify_crossfade_added (Crossfade *);
 	void flush_notifications ();
@@ -101,7 +74,7 @@ class AudioPlaylist : public ARDOUR::Playlist
        ~AudioPlaylist (); /* public should use unref() */
 
     private:
-       Crossfades      _crossfades;
+       Crossfades      _crossfades;    /* xfades currently in use */
        Crossfades      _pending_xfade_adds;
 
        void crossfade_invalidated (Crossfade*);
diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index c9cb2b8152..4be5d27a6b 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -42,18 +42,6 @@ class Session;
 class AudioFilter;
 class AudioSource;
 
-struct AudioRegionState : public RegionState 
-{
-	AudioRegionState (std::string why);
-
-	Curve    _fade_in;
-	Curve    _fade_out;
-	Curve    _envelope;
-	gain_t   _scale_amplitude;
-	uint32_t _fade_in_disabled;
-	uint32_t _fade_out_disabled;
-};
-
 class AudioRegion : public Region
 {
   public:
@@ -131,8 +119,6 @@ class AudioRegion : public Region
 
 	int separate_by_channel (ARDOUR::Session&, vector<AudioRegion*>&) const;
 
-	UndoAction get_memento() const;
-
 	/* filter */
 
 	int apply (AudioFilter&);
@@ -167,9 +153,6 @@ class AudioRegion : public Region
 	void set_default_fade_out ();
 	void set_default_envelope ();
 
-	StateManager::State* state_factory (std::string why) const;
-	Change restore_state (StateManager::State&);
-
 	void recompute_gain_at_end ();
 	void recompute_gain_at_start ();
 
@@ -204,6 +187,9 @@ class AudioRegion : public Region
 	gain_t            _scale_amplitude;
 	uint32_t          _fade_in_disabled;
 	uint32_t          _fade_out_disabled;
+
+  protected:
+	int set_live_state (const XMLNode&, Change&, bool send);
 };
 
 } /* namespace ARDOUR */
diff --git a/libs/ardour/ardour/crossfade.h b/libs/ardour/ardour/crossfade.h
index 7fd7323b36..d1b2e8f1e1 100644
--- a/libs/ardour/ardour/crossfade.h
+++ b/libs/ardour/ardour/crossfade.h
@@ -33,7 +33,6 @@
 #include <ardour/ardour.h>
 #include <ardour/curve.h>
 #include <ardour/audioregion.h>
-#include <ardour/state_manager.h>
 #include <ardour/crossfade_compare.h>
 
 namespace ARDOUR {
@@ -41,19 +40,7 @@ namespace ARDOUR {
 class AudioRegion;
 class Playlist;
 
-struct CrossfadeState : public StateManager::State {
-    CrossfadeState (std::string reason) : StateManager::State (reason) {}
-
-    UndoAction fade_in_memento;
-    UndoAction fade_out_memento;
-    nframes_t position;
-    nframes_t length;
-    AnchorPoint    anchor_point;
-    bool           follow_overlap;
-    bool           active;
-};
-
-class Crossfade : public PBD::StatefulDestructible, public StateManager
+class Crossfade : public PBD::StatefulDestructible
 {
   public:
 
@@ -122,6 +109,7 @@ class Crossfade : public PBD::StatefulDestructible, public StateManager
 	nframes_t position() const { return _position; }
 
 	sigc::signal<void,Crossfade*> Invalidated;
+	sigc::signal<void,Change>     StateChanged;
 
 	bool covers (nframes_t frame) const {
 		return _position <= frame && frame < _position + _length;
@@ -129,8 +117,6 @@ class Crossfade : public PBD::StatefulDestructible, public StateManager
 
 	OverlapType coverage (nframes_t start, nframes_t end) const;
 
-	UndoAction get_memento() const;	
-
 	static void set_buffer_size (nframes_t);
 
 	bool active () const { return _active; }
@@ -172,15 +158,11 @@ class Crossfade : public PBD::StatefulDestructible, public StateManager
 	static Sample* crossfade_buffer_out;
 	static Sample* crossfade_buffer_in;
 
-	void initialize (bool savestate=true);
+	void initialize ();
 	int  compute (boost::shared_ptr<ARDOUR::AudioRegion>, boost::shared_ptr<ARDOUR::AudioRegion>, CrossfadeModel);
 	bool update (bool force);
 
-	StateManager::State* state_factory (std::string why) const;
-	Change restore_state (StateManager::State&);
-
 	void member_changed (ARDOUR::Change);
-
 };
 
 
diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index 4c2e75c6c9..8f08c58466 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -40,14 +40,13 @@
 #include <ardour/ardour.h>
 #include <ardour/crossfade_compare.h>
 #include <ardour/location.h>
-#include <ardour/state_manager.h>
 
 namespace ARDOUR  {
 
 class Session;
 class Region;
 
-class Playlist : public StateManager, public PBD::StatefulDestructible {
+class Playlist : public PBD::StatefulDestructible {
   public:
 	typedef list<boost::shared_ptr<Region> >    RegionList;
 
@@ -56,9 +55,8 @@ class Playlist : public StateManager, public PBD::StatefulDestructible {
 	Playlist (const Playlist&, string name, bool hidden = false);
 	Playlist (const Playlist&, nframes_t start, nframes_t cnt, string name, bool hidden = false);
 
-	virtual void clear (bool with_save = true);
+	virtual void clear ();
 	virtual void dump () const;
-	virtual UndoAction get_memento() const = 0;
 
 	void ref();
 	void unref();
@@ -80,7 +78,7 @@ class Playlist : public StateManager, public PBD::StatefulDestructible {
 
 	/* Editing operations */
 
-	void add_region (boost::shared_ptr<Region>, nframes_t position, float times = 1, bool with_save = true);
+	void add_region (boost::shared_ptr<Region>, nframes_t position, float times = 1);
 	void remove_region (boost::shared_ptr<Region>);
 	void get_equivalent_regions (boost::shared_ptr<Region>, std::vector<boost::shared_ptr<Region> >&);
 	void get_region_list_equivalent_regions (boost::shared_ptr<Region>, std::vector<boost::shared_ptr<Region> >&);
@@ -111,8 +109,6 @@ class Playlist : public StateManager, public PBD::StatefulDestructible {
 	int set_state (const XMLNode&);
 	XMLNode& get_template ();
 
-	sigc::signal<void,boost::shared_ptr<Region> > RegionAdded;
-	sigc::signal<void,boost::shared_ptr<Region> > RegionRemoved;
 	sigc::signal<void,Playlist*,bool> InUse;
 	sigc::signal<void>                Modified;
 	sigc::signal<void>                NameChanged;
@@ -169,13 +165,12 @@ class Playlist : public StateManager, public PBD::StatefulDestructible {
 	friend class RegionLock;
 
 	RegionList       regions;  /* the current list of regions in the playlist */
+	std::set<boost::shared_ptr<Region> > all_regions; /* all regions ever added to this playlist */
 	string          _name;
 	Session&        _session;
 	mutable gint    block_notifications;
 	mutable gint    ignore_state_changes;
 	mutable Glib::Mutex region_lock;
-	RegionList       pending_removals;
-	RegionList       pending_adds;
 	RegionList       pending_bounds;
 	bool             pending_modified;
 	bool             pending_length;
@@ -244,10 +239,7 @@ class Playlist : public StateManager, public PBD::StatefulDestructible {
 
 	virtual XMLNode& state (bool);
 
-	/* override state_manager::save_state so we can check in_set_state() */
-
-	void save_state (std::string why);
-	void maybe_save_state (std::string why);
+	boost::shared_ptr<Region> region_by_id (PBD::ID);
 
 	void add_region_internal (boost::shared_ptr<Region>, nframes_t position, bool delay_sort = false);
 
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index 30cd3267df..67e00d0ee8 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -28,7 +28,6 @@
 #include <pbd/statefuldestructible.h> 
 
 #include <ardour/ardour.h>
-#include <ardour/state_manager.h>
 
 class XMLNode;
 
@@ -42,21 +41,7 @@ enum RegionEditState {
 	EditChangesID      = 2
 };
 
-struct RegionState : public StateManager::State
-{
-	RegionState (std::string why) : StateManager::State (why) {}
-
-	nframes_t          _start;
-	nframes_t          _length;
-	nframes_t          _position;
-	uint32_t                _flags;
-	nframes_t          _sync_position;
-	layer_t        	        _layer;
-	string                  _name;        
-	mutable RegionEditState _first_edit;
-};
-
-class Region : public PBD::StatefulDestructible, public StateManager, public boost::enable_shared_from_this<Region>
+class Region : public PBD::StatefulDestructible, public boost::enable_shared_from_this<Region>
 {
   public:
 	enum Flag {
@@ -92,6 +77,8 @@ class Region : public PBD::StatefulDestructible, public StateManager, public boo
 	static Change LayerChanged;
 	static Change HiddenChanged;
 
+	sigc::signal<void,Change> StateChanged;
+
 	virtual ~Region();
 
 	/* Note: changing the name of a Region does not constitute an edit */
@@ -176,8 +163,6 @@ class Region : public PBD::StatefulDestructible, public StateManager, public boo
 
 	ARDOUR::Playlist* playlist() const { return _playlist; }
 
-	virtual UndoAction get_memento() const = 0;
-
 	void set_playlist (ARDOUR::Playlist*);
 
 	virtual void lock_sources () {}
@@ -188,6 +173,7 @@ class Region : public PBD::StatefulDestructible, public StateManager, public boo
 	XMLNode&         get_state ();
 	virtual XMLNode& state (bool);
 	virtual int      set_state (const XMLNode&);
+	virtual int      set_live_state (const XMLNode&, Change&, bool send);
 
 	virtual boost::shared_ptr<Region> get_parent() = 0;
 	
@@ -207,15 +193,8 @@ class Region : public PBD::StatefulDestructible, public StateManager, public boo
   protected:
 	XMLNode& get_short_state (); /* used only by Session */
 
-	/* state management */
-
 	void send_change (Change);
 
-	/* derived classes need these during their own state management calls */
-
-	void   store_state (RegionState&) const;
-	Change restore_and_return_flags (RegionState&);
-	
 	void trim_to_internal (nframes_t position, nframes_t length, void *src);
 
 	bool copied() const { return _flags & Copied; }
diff --git a/libs/ardour/audio_playlist.cc b/libs/ardour/audio_playlist.cc
index 2d2f4e5365..e39be5d402 100644
--- a/libs/ardour/audio_playlist.cc
+++ b/libs/ardour/audio_playlist.cc
@@ -39,10 +39,6 @@ using namespace sigc;
 using namespace std;
 using namespace PBD;
 
-AudioPlaylist::State::~State ()
-{
-}
-
 AudioPlaylist::AudioPlaylist (Session& session, const XMLNode& node, bool hidden)
 	: Playlist (session, node, hidden)
 {
@@ -50,8 +46,6 @@ AudioPlaylist::AudioPlaylist (Session& session, const XMLNode& node, bool hidden
 	set_state (node);
 	in_set_state = false;
 
-	save_state (_("initial state"));
-
 	if (!hidden) {
 		PlaylistCreated (this); /* EMIT SIGNAL */
 	}
@@ -60,8 +54,6 @@ AudioPlaylist::AudioPlaylist (Session& session, const XMLNode& node, bool hidden
 AudioPlaylist::AudioPlaylist (Session& session, string name, bool hidden)
 	: Playlist (session, name, hidden)
 {
-	save_state (_("initial state"));
-
 	if (!hidden) {
 		PlaylistCreated (this); /* EMIT SIGNAL */
 	}
@@ -71,8 +63,6 @@ AudioPlaylist::AudioPlaylist (Session& session, string name, bool hidden)
 AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, string name, bool hidden)
 	: Playlist (other, name, hidden)
 {
-	save_state (_("initial state"));
-
 	RegionList::const_iterator in_o  = other.regions.begin();
 	RegionList::iterator in_n = regions.begin();
 
@@ -118,8 +108,6 @@ AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, string name, bool hidd
 AudioPlaylist::AudioPlaylist (const AudioPlaylist& other, nframes_t start, nframes_t cnt, string name, bool hidden)
 	: Playlist (other, start, cnt, name, hidden)
 {
-	save_state (_("initial state"));
-
 	/* this constructor does NOT notify others (session) */
 }
 
@@ -134,24 +122,7 @@ AudioPlaylist::~AudioPlaylist ()
 	notify_callbacks ();
 
 	for (Crossfades::iterator x = _crossfades.begin(); x != _crossfades.end(); ++x) {
-		all_xfades.insert (*x);
-	}
-
-	for (StateMap::iterator i = states.begin(); i != states.end(); ++i) {
-		
-		AudioPlaylist::State* apstate = dynamic_cast<AudioPlaylist::State*> (*i);
-
-	for (Crossfades::iterator xf = apstate->crossfades.begin(); xf != apstate->crossfades.end(); ++xf) {
-			all_xfades.insert (*xf);
-		}
-
-		delete apstate;
-	}
-
-	/* delete every crossfade */
-
-	for (set<Crossfade *>::iterator axf = all_xfades.begin(); axf != all_xfades.end(); ++axf) {
-		delete *axf;
+		delete *x;
 	}
 }
 
@@ -447,7 +418,7 @@ AudioPlaylist::check_dependents (boost::shared_ptr<Region> r, bool norefresh)
 					add_crossfade (*xfade);
 					
 				} else {
-		
+
 					xfade = new Crossfade (other, region, Config->get_xfade_model(), Config->get_crossfades_active());
 					add_crossfade (*xfade);
 				}
@@ -519,7 +490,7 @@ AudioPlaylist::set_state (const XMLNode& node)
 
 	if (!in_set_state) {
 		Playlist::set_state (node);
-	}
+	} 
 
 	nlist = node.children();
 
@@ -527,155 +498,60 @@ AudioPlaylist::set_state (const XMLNode& node)
 
 		child = *niter;
 
-		if (child->name() == "Crossfade") {
-
-			Crossfade *xfade;
-			
-			try {
-				xfade = new Crossfade (*((const Playlist *)this), *child);
-			}
-
-			catch (failed_constructor& err) {
-			  //	cout << string_compose (_("could not create crossfade object in playlist %1"),
-			  //	  _name) 
-			  //    << endl;
-				continue;
-			}
-
-			Crossfades::iterator ci;
-
-			for (ci = _crossfades.begin(); ci != _crossfades.end(); ++ci) {
-				if (*(*ci) == *xfade) {
-					break;
-				}
-			}
-
-			if (ci == _crossfades.end()) {
-				_crossfades.push_back (xfade);
-				xfade->Invalidated.connect (mem_fun (*this, &AudioPlaylist::crossfade_invalidated));
-				xfade->StateChanged.connect (mem_fun (*this, &AudioPlaylist::crossfade_changed));
-				NewCrossfade(xfade);
-			} else {
-				delete xfade;
-			}
+		if (child->name() != "Crossfade") {
+			continue;
 		}
 
-	}
-
-	return 0;
-}
-
-void
-AudioPlaylist::drop_all_states ()
-{
-	set<Crossfade*> all_xfades;
-	set<boost::shared_ptr<Region> > all_regions;
-
-	/* find every region we've ever used, and add it to the set of 
-	   all regions. same for xfades;
-	*/
-
-	for (StateMap::iterator i = states.begin(); i != states.end(); ++i) {
+		Crossfade *xfade;
 		
-		AudioPlaylist::State* apstate = dynamic_cast<AudioPlaylist::State*> (*i);
-
-		for (RegionList::iterator r = apstate->regions.begin(); r != apstate->regions.end(); ++r) {
-			all_regions.insert (*r);
-		}
-
-		for (Crossfades::iterator xf = apstate->crossfades.begin(); xf != apstate->crossfades.end(); ++xf) {
-			all_xfades.insert (*xf);
+		try {
+			xfade = new Crossfade (*((const Playlist *)this), *child);
 		}
-	}
-
-	/* now remove from the "all" lists every region that is in the current list. */
-
-	for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
-		set<boost::shared_ptr<Region> >::iterator x = all_regions.find (*i);
-		if (x != all_regions.end()) {
-			all_regions.erase (x);
+		
+		catch (failed_constructor& err) {
+			//	cout << string_compose (_("could not create crossfade object in playlist %1"),
+			//	  _name) 
+			//    << endl;
+			continue;
 		}
-	}
-
-	/* ditto for every crossfade */
-
-	for (list<Crossfade*>::iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-		set<Crossfade*>::iterator x = all_xfades.find (*i);
-		if (x != all_xfades.end()) {
-			all_xfades.erase (x);
+		
+		Crossfades::iterator ci;
+		
+		for (ci = _crossfades.begin(); ci != _crossfades.end(); ++ci) {
+			if (*(*ci) == *xfade) {
+				break;
+			}
 		}
-	}
-
-	/* delete every crossfade that is left (ditto as per regions) */
-
-	for (set<Crossfade *>::iterator axf = all_xfades.begin(); axf != all_xfades.end(); ++axf) {
-		delete *axf;
-	}
-
-	/* Now do the generic thing ... */
-
-	StateManager::drop_all_states ();
-}
-
-StateManager::State*
-AudioPlaylist::state_factory (std::string why) const
-{
-	State* state = new State (why);
-
-	state->regions = regions;
-	state->region_states.clear ();
-	for (RegionList::const_iterator i = regions.begin(); i != regions.end(); ++i) {
-		state->region_states.push_back ((*i)->get_memento());
-	}
-
-	state->crossfades = _crossfades;
-	state->crossfade_states.clear ();
-	for (Crossfades::const_iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
-		state->crossfade_states.push_back ((*i)->get_memento());
-	}
-	return state;
-}
-
-Change
-AudioPlaylist::restore_state (StateManager::State& state)
-{ 
-	{ 
-		RegionLock rlock (this);
-		State* apstate = dynamic_cast<State*> (&state);
-
-		in_set_state = true;
+		
+		if (ci == _crossfades.end()) {
+			_crossfades.push_back (xfade);
+			xfade->Invalidated.connect (mem_fun (*this, &AudioPlaylist::crossfade_invalidated));
+			xfade->StateChanged.connect (mem_fun (*this, &AudioPlaylist::crossfade_changed));
+			NewCrossfade(xfade);
+		} else {
 
-		regions = apstate->regions;
+			/* adjust the current state of the existing crossfade */
 
-		for (list<UndoAction>::iterator s = apstate->region_states.begin(); s != apstate->region_states.end(); ++s) {
-			(*s) ();
-		}
+			(*ci)->set_state (*child);
 
-		_crossfades = apstate->crossfades;
-		
-		for (list<UndoAction>::iterator s = apstate->crossfade_states.begin(); s != apstate->crossfade_states.end(); ++s) {
-			(*s) ();
+			/* drop the new one */
+			delete xfade;
 		}
-
-		in_set_state = false;
 	}
 
-	notify_length_changed ();
-	return Change (~0);
-}
-
-UndoAction
-AudioPlaylist::get_memento () const
-{
-	return sigc::bind (mem_fun (*(const_cast<AudioPlaylist*> (this)), &StateManager::use_state), _current_state_id);
+	return 0;
 }
 
 void
-AudioPlaylist::clear (bool with_save)
+AudioPlaylist::clear ()
 {
+	for (Crossfades::iterator i = _crossfades.begin(); i != _crossfades.end(); ++i) {
+		delete *i;
+	}
+
 	_crossfades.clear ();
 	
-	Playlist::clear (with_save);
+	Playlist::clear ();
 }
 
 XMLNode&
@@ -776,52 +652,6 @@ AudioPlaylist::destroy_region (boost::shared_ptr<Region> region)
 		c = ctmp;
 	}
 
-	for (StateMap::iterator s = states.begin(); s != states.end(); ) {
-		StateMap::iterator tmp;
-
-		tmp = s;
-		++tmp;
-
-		State* astate = dynamic_cast<State*> (*s);
-		
-		for (c = astate->crossfades.begin(); c != astate->crossfades.end(); ) {
-
-			ctmp = c;
-			++ctmp;
-
-			if ((*c)->involves (r)) {
-				unique_xfades.insert (*c);
-				_crossfades.erase (c);
-			}
-
-			c = ctmp;
-		}
-
-		list<UndoAction>::iterator rsi, rsitmp;
-		RegionList::iterator ri, ritmp;
-
-		for (ri = astate->regions.begin(), rsi = astate->region_states.begin(); 
-		     ri != astate->regions.end() && rsi != astate->region_states.end();) {
-
-
-			ritmp = ri;
-			++ritmp;
-
-			rsitmp = rsi; 
-			++rsitmp;
-
-			if (region == (*ri)) {
-				astate->regions.erase (ri);
-				astate->region_states.erase (rsi);
-			}
-
-			ri = ritmp;
-			rsi = rsitmp;
-		}
-		
-		s = tmp;
-	}
-
 	for (set<Crossfade*>::iterator c = unique_xfades.begin(); c != unique_xfades.end(); ++c) {
 		delete *c;
 	}
@@ -847,8 +677,6 @@ AudioPlaylist::crossfade_changed (Change ignored)
 	   that occured.
 	*/
 
-	maybe_save_state (_("xfade change"));
-
 	notify_modified ();
 }
 
@@ -870,8 +698,6 @@ AudioPlaylist::region_changed (Change what_changed, boost::shared_ptr<Region> re
 
 	parent_wants_notify = Playlist::region_changed (what_changed, region);
 
-	maybe_save_state (_("region modified"));
-
 	if ((parent_wants_notify || (what_changed & our_interests))) {
 		notify_modified ();
 	}
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 1a09cad032..a2a86f6a95 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -58,14 +58,6 @@ Change AudioRegion::EnvelopeActiveChanged = ARDOUR::new_change();
 Change AudioRegion::ScaleAmplitudeChanged = ARDOUR::new_change();
 Change AudioRegion::EnvelopeChanged       = ARDOUR::new_change();
 
-AudioRegionState::AudioRegionState (string why)
-	: RegionState (why),
-	  _fade_in (0.0, 2.0, 1.0, false),
-	  _fade_out (0.0, 2.0, 1.0, false),
-	  _envelope (0.0, 2.0, 1.0, false)
-{
-}
-
 AudioRegion::AudioRegion (boost::shared_ptr<AudioSource> src, nframes_t start, nframes_t length)
 	: Region (start, length, PBD::basename_nosuffix(src->name()), 0,  Region::Flag(Region::DefaultFlags|Region::External)),
 	  _fade_in (0.0, 2.0, 1.0, false),
@@ -88,8 +80,6 @@ AudioRegion::AudioRegion (boost::shared_ptr<AudioSource> src, nframes_t start, n
 	set_default_fades ();
 	set_default_envelope ();
 
-	save_state ("initial state");
-
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
 
@@ -114,7 +104,6 @@ AudioRegion::AudioRegion (boost::shared_ptr<AudioSource> src, nframes_t start, n
 
 	set_default_fades ();
 	set_default_envelope ();
-	save_state ("initial state");
 
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
@@ -142,7 +131,6 @@ AudioRegion::AudioRegion (SourceList& srcs, nframes_t start, nframes_t length, c
 
 	set_default_fades ();
 	set_default_envelope ();
-	save_state ("initial state");
 
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
@@ -208,8 +196,6 @@ AudioRegion::AudioRegion (boost::shared_ptr<const AudioRegion> other, nframes_t
 
 	_scale_amplitude = other->_scale_amplitude;
 
-	save_state ("initial state");
-
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
 
@@ -251,8 +237,6 @@ AudioRegion::AudioRegion (boost::shared_ptr<const AudioRegion> other)
 	_fade_in_disabled = 0;
 	_fade_out_disabled = 0;
 	
-	save_state ("initial state");
-
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
 
@@ -277,8 +261,6 @@ AudioRegion::AudioRegion (boost::shared_ptr<AudioSource> src, const XMLNode& nod
 		throw failed_constructor();
 	}
 
-	save_state ("initial state");
-
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
 
@@ -319,8 +301,6 @@ AudioRegion::AudioRegion (SourceList& srcs, const XMLNode& node)
 		throw failed_constructor();
 	}
 
-	save_state ("initial state");
-
 	_envelope.StateChanged.connect (mem_fun (*this, &AudioRegion::envelope_changed));
 }
 
@@ -330,88 +310,6 @@ AudioRegion::~AudioRegion ()
 	GoingAway (); /* EMIT SIGNAL */
 }
 
-StateManager::State*
-AudioRegion::state_factory (std::string why) const
-{
-	AudioRegionState* state = new AudioRegionState (why);
-
-	Region::store_state (*state);
-
-	state->_fade_in = _fade_in;
-	state->_fade_out = _fade_out;
-	state->_envelope = _envelope;
-	state->_scale_amplitude = _scale_amplitude;
-	state->_fade_in_disabled = _fade_in_disabled;
-	state->_fade_out_disabled = _fade_out_disabled;
-
-	return state;
-}	
-
-Change
-AudioRegion::restore_state (StateManager::State& sstate) 
-{
-	AudioRegionState* state = dynamic_cast<AudioRegionState*> (&sstate);
-
-	Change what_changed = Region::restore_and_return_flags (*state);
-	
-	if (_flags != Flag (state->_flags)) {
-		
-		uint32_t old_flags = _flags;
-		
-		_flags = Flag (state->_flags);
-		
-		if ((old_flags ^ state->_flags) & EnvelopeActive) {
-			what_changed = Change (what_changed|EnvelopeActiveChanged);
-		}
-	}
-		
-	if (!(_fade_in == state->_fade_in)) {
-		_fade_in = state->_fade_in;
-		what_changed = Change (what_changed|FadeInChanged);
-	}
-
-	if (!(_fade_out == state->_fade_out)) {
-		_fade_out = state->_fade_out;
-		what_changed = Change (what_changed|FadeOutChanged);
-	}
-
-	if (_scale_amplitude != state->_scale_amplitude) {
-		_scale_amplitude = state->_scale_amplitude;
-		what_changed = Change (what_changed|ScaleAmplitudeChanged);
-	}
-
-	if (_fade_in_disabled != state->_fade_in_disabled) {
-		if (_fade_in_disabled == 0 && state->_fade_in_disabled) {
-			set_fade_in_active (false);
-		} else if (_fade_in_disabled && state->_fade_in_disabled == 0) {
-			set_fade_in_active (true);
-		}
-		_fade_in_disabled = state->_fade_in_disabled;
-	}
-		
-	if (_fade_out_disabled != state->_fade_out_disabled) {
-		if (_fade_out_disabled == 0 && state->_fade_out_disabled) {
-			set_fade_out_active (false);
-		} else if (_fade_out_disabled && state->_fade_out_disabled == 0) {
-			set_fade_out_active (true);
-		}
-		_fade_out_disabled = state->_fade_out_disabled;
-	}
-
-	/* XXX need a way to test stored state versus current for envelopes */
-
-	_envelope = state->_envelope;
-	what_changed = Change (what_changed);
-
-	return what_changed;
-}
-
-UndoAction
-AudioRegion::get_memento() const
-{
-	return sigc::bind (mem_fun (*(const_cast<AudioRegion *> (this)), &StateManager::use_state), _current_state_id);
-}
-
 bool
 AudioRegion::verify_length (nframes_t len)
 {
@@ -482,11 +380,7 @@ AudioRegion::set_envelope_active (bool yn)
 			snprintf (buf, sizeof (buf), "envelope off");
 			_flags = Flag (_flags & ~EnvelopeActive);
 		}
-		if (!_frozen) {
-			save_state (buf);
-		}
 		send_change (EnvelopeActiveChanged);
-
 	}
 }
 
@@ -706,6 +600,8 @@ AudioRegion::state (bool full)
 		} else {
 			_fade_in.store_state (*child);
 		}
+
+		child->add_property (X_("active"), _fade_in_disabled ? X_("no") : X_("yes"));
 		
 		child = node.add_child (X_("FadeOut"));
 		
@@ -714,6 +610,8 @@ AudioRegion::state (bool full)
 		} else {
 			_fade_out.store_state (*child);
 		}
+
+		child->add_property (X_("active"), _fade_out_disabled ? X_("no") : X_("yes"));
 	}
 	
 	child = node.add_child ("Envelope");
@@ -736,6 +634,7 @@ AudioRegion::state (bool full)
 		} else {
 			_envelope.store_state (*child);
 		}
+
 	} else {
 		child->add_property ("default", "yes");
 	}
@@ -748,14 +647,16 @@ AudioRegion::state (bool full)
 }
 
 int
-AudioRegion::set_state (const XMLNode& node)
+AudioRegion::set_live_state (const XMLNode& node, Change& what_changed, bool send)
 {
 	const XMLNodeList& nlist = node.children();
 	const XMLProperty *prop;
 	LocaleGuard lg (X_("POSIX"));
 
-	Region::set_state (node);
+	Region::set_live_state (node, what_changed, false);
 
+	uint32_t old_flags = _flags;
+		
 	if ((prop = node.property ("flags")) != 0) {
 		_flags = Flag (strtol (prop->value().c_str(), (char **) 0, 16));
 
@@ -763,6 +664,16 @@ AudioRegion::set_state (const XMLNode& node)
 		_flags = Flag (_flags & ~Region::RightOfSplit);
 	}
 
+	if ((old_flags ^ _flags) & Muted) {
+		what_changed = Change (what_changed|MuteChanged);
+	}
+	if ((old_flags ^ _flags) & Opaque) {
+		what_changed = Change (what_changed|OpacityChanged);
+	}
+	if ((old_flags ^ _flags) & Locked) {
+		what_changed = Change (what_changed|LockChanged);
+	}
+
 	if ((prop = node.property ("scale-gain")) != 0) {
 		_scale_amplitude = atof (prop->value().c_str());
 	} else {
@@ -798,7 +709,6 @@ AudioRegion::set_state (const XMLNode& node)
 			if ((prop = child->property ("default")) != 0 || (prop = child->property ("steepness")) != 0) {
 				set_default_fade_in ();
 			} else {
-				
 				_fade_in.load_state (*child);
 			}
 
@@ -814,9 +724,24 @@ AudioRegion::set_state (const XMLNode& node)
 		} 
 	}
 
+	if (send) {
+		send_change (what_changed);
+	}
+
 	return 0;
 }
 
+int
+AudioRegion::set_state (const XMLNode& node)
+{
+	/* Region::set_state() calls the virtual set_live_state(),
+	   which will get us back to AudioRegion::set_live_state()
+	   to handle the relevant stuff.
+	*/
+
+	return Region::set_state (node);
+}
+
 void
 AudioRegion::set_fade_in_shape (FadeShape shape)
 {
@@ -886,10 +811,6 @@ AudioRegion::set_fade_in (FadeShape shape, nframes_t len)
 	_fade_in.thaw ();
 	_fade_in_shape = shape;
 
-	if (!_frozen) {
-		save_state (_("fade in change"));
-	}
-
 	send_change (FadeInChanged);
 }
 
@@ -948,10 +869,6 @@ AudioRegion::set_fade_out (FadeShape shape, nframes_t len)
 	_fade_out.thaw ();
 	_fade_out_shape = shape;
 
-	if (!_frozen) {
-		save_state (_("fade in change"));
-	}
-
 	send_change (FadeOutChanged);
 }
 
@@ -962,13 +879,6 @@ AudioRegion::set_fade_in_length (nframes_t len)
 
 	if (changed) {
 		_flags = Flag (_flags & ~DefaultFadeIn);
-
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "fade in length changed to %u", len);
-			save_state (buf);
-		}
-		
 		send_change (FadeInChanged);
 	}
 }
@@ -980,12 +890,6 @@ AudioRegion::set_fade_out_length (nframes_t len)
 
 	if (changed) {
 		_flags = Flag (_flags & ~DefaultFadeOut);
-		
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "fade out length changed to %u", len);
-			save_state (buf);
-		}
 	}
 
 	send_change (FadeOutChanged);
@@ -1324,12 +1228,6 @@ AudioRegion::normalize_to (float target_dB)
 
 	_scale_amplitude = target/maxamp;
 
-	if (!_frozen) {
-		char buf[64];
-		snprintf (buf, sizeof (buf), _("normalized to %.2fdB"), target_dB);
-		save_state (buf);
-	}
-
 	/* tell the diskstream we're in */
 
 	if (_playlist) {
@@ -1344,7 +1242,6 @@ AudioRegion::normalize_to (float target_dB)
 void
 AudioRegion::envelope_changed (Change ignored)
 {
-	save_state (_("envelope change"));
 	send_change (EnvelopeChanged);
 }
 
diff --git a/libs/ardour/auditioner.cc b/libs/ardour/auditioner.cc
index 7bf9f0542a..0c5e8bc6a2 100644
--- a/libs/ardour/auditioner.cc
+++ b/libs/ardour/auditioner.cc
@@ -78,7 +78,7 @@ Auditioner::prepare_playlist ()
 	AudioPlaylist* const apl = dynamic_cast<AudioPlaylist*>(_diskstream->playlist());
 	assert(apl);
 
-	apl->clear (false);
+	apl->clear ();
 	return *apl;
 }
 
@@ -126,8 +126,8 @@ Auditioner::audition_region (boost::shared_ptr<Region> region)
 	boost::shared_ptr<AudioRegion> the_region (boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (region)));
 	the_region->set_position (0, this);
 
-	_diskstream->playlist()->clear (false);
-	_diskstream->playlist()->add_region (the_region, 0, 1, false);
+	_diskstream->playlist()->clear ();
+	_diskstream->playlist()->add_region (the_region, 0, 1);
 
 	while (_diskstream->n_channels() < the_region->n_channels()) {
 		audio_diskstream()->add_channel ();
diff --git a/libs/ardour/crossfade.cc b/libs/ardour/crossfade.cc
index 32a9e2b533..a197459971 100644
--- a/libs/ardour/crossfade.cc
+++ b/libs/ardour/crossfade.cc
@@ -151,28 +151,24 @@ Crossfade::Crossfade (const Playlist& playlist, XMLNode& node)
 	}
 
 	_length = 0;
-	initialize(false);
+	initialize();
 	
 	if (set_state (node)) {
 		throw failed_constructor();
 	}
-
-	save_state ("initial");
 }
 
 Crossfade::Crossfade (const Crossfade &orig, boost::shared_ptr<AudioRegion> newin, boost::shared_ptr<AudioRegion> newout)
 	: _fade_in(orig._fade_in),
 	  _fade_out(orig._fade_out)
 {
-	_active 			= orig._active;
-	_in_update 			= orig._in_update;
-	_length 			= orig._length;
-	_position 			= orig._position;
-	_anchor_point 		= orig._anchor_point;
-	_follow_overlap 	= orig._follow_overlap;
-	_fixed 				= orig._fixed;
-	_follow_overlap 	= orig._follow_overlap;
-	_short_xfade_length = orig._short_xfade_length;
+	_active           = orig._active;
+	_in_update        = orig._in_update;
+	_length           = orig._length;
+	_position         = orig._position;
+	_anchor_point     = orig._anchor_point;
+	_follow_overlap   = orig._follow_overlap;
+	_fixed            = orig._fixed;
 	
 	_in = newin;
 	_out = newout;
@@ -192,13 +188,10 @@ Crossfade::Crossfade (const Crossfade &orig, boost::shared_ptr<AudioRegion> newi
 
 Crossfade::~Crossfade ()
 {
-	for (StateMap::iterator i = states.begin(); i != states.end(); ++i) {
-		delete *i;
-	}
 }
 
 void
-Crossfade::initialize (bool savestate)
+Crossfade::initialize ()
 {
 	_in_update = false;
 	
@@ -225,14 +218,10 @@ Crossfade::initialize (bool savestate)
 	_fade_in.add (_length, 1.0);
 	_fade_in.thaw ();
 
-//	_in->StateChanged.connect (slot (*this, &Crossfade::member_changed));
-//	_out->StateChanged.connect (slot (*this, &Crossfade::member_changed));
+	_in->StateChanged.connect (sigc::mem_fun (*this, &Crossfade::member_changed));
+	_out->StateChanged.connect (sigc::mem_fun (*this, &Crossfade::member_changed));
 
 	overlap_type = _in->coverage (_out->position(), _out->last_frame());
-
-	if (savestate) {
-		save_state ("initial");
-	}
 }	
 
 int
@@ -488,8 +477,7 @@ Crossfade::set_active (bool yn)
 {
 	if (_active != yn) {
 		_active = yn;
-		save_state (_("active changed"));
-		send_state_changed (ActiveChanged);
+		StateChanged (ActiveChanged);
 	}
 }
 
@@ -535,7 +523,6 @@ bool
 Crossfade::update (bool force)
 {
 	nframes_t newlen;
-	bool save = false;
 
 	if (_follow_overlap) {
 		newlen = _out->first_frame() + _out->length() - _in->first_frame();
@@ -559,41 +546,32 @@ Crossfade::update (bool force)
 		
 		_length = newlen;
 
-		save = true;
-
 	} 
 
 	switch (_anchor_point) {
 	case StartOfIn:
 		if (_position != _in->first_frame()) {
 			_position = _in->first_frame();
-			save = true;
 		}
 		break;
 
 	case EndOfIn:
 		if (_position != _in->last_frame() - _length) {
 			_position = _in->last_frame() - _length;
-			save = true;
 		}
 		break;
 
 	case EndOfOut:
 		if (_position != _out->last_frame() - _length) {
 			_position = _out->last_frame() - _length;
-			save = true;
 		}
 	}
 
-	if (save) {
-		save_state ("updated");
-	} 
-
 	/* UI's may need to know that the overlap changed even 
 	   though the xfade length did not.
 	*/
 	
-	send_state_changed (BoundsChanged); /* EMIT SIGNAL */
+	StateChanged (BoundsChanged); /* EMIT SIGNAL */
 
 	_in_update = false;
 
@@ -612,65 +590,6 @@ Crossfade::member_changed (Change what_changed)
 	}
 }
 
-Change
-Crossfade::restore_state (StateManager::State& state)
-{
-	CrossfadeState* xfstate = dynamic_cast<CrossfadeState*> (&state);
-	Change what_changed = Change (0);
-
-	_in_update = true;
-	
-	xfstate->fade_in_memento ();
-	xfstate->fade_out_memento ();
-
-	if (_length != xfstate->length) {
-		what_changed = Change (what_changed|LengthChanged);
-		_length = xfstate->length;
-	}
-	if (_active != xfstate->active) {
-		what_changed = Change (what_changed|ActiveChanged);
-		_active = xfstate->active;
-	}
-	if (_position != xfstate->position) {
-		what_changed = Change (what_changed|PositionChanged);
-		_position = xfstate->position;
-	}
-
-	/* XXX what to do about notifications for these? I don't
-	   think (G)UI cares about them because they are
-	   implicit in the bounds.
-	*/
-
-	_follow_overlap = xfstate->follow_overlap;
-	_anchor_point = xfstate->anchor_point;
-
-	_in_update = false;
-
-	return Change (what_changed);
-}
-
-StateManager::State*
-Crossfade::state_factory (std::string why) const
-{
-	CrossfadeState* state = new CrossfadeState (why);
-
-	state->fade_in_memento = _fade_in.get_memento ();
-	state->fade_out_memento = _fade_out.get_memento ();
-	state->active = _active;
-	state->length = _length;
-	state->position = _position;
-	state->follow_overlap = _follow_overlap;
-	state->anchor_point = _anchor_point;
-
-	return state;
-}
-	
-UndoAction
-Crossfade::get_memento() const
-{
-  return sigc::bind (mem_fun (*(const_cast<Crossfade *> (this)), &StateManager::use_state), _current_state_id);
-}
-
 XMLNode&
 Crossfade::get_state () 
 {
@@ -733,16 +652,26 @@ Crossfade::set_state (const XMLNode& node)
 	XMLNode* fo;
 	const XMLProperty* prop;
 	LocaleGuard lg (X_("POSIX"));
+	Change what_changed = Change (0);
+	nframes_t val;
 
 	if ((prop = node.property ("position")) != 0) {
-		_position = atoi (prop->value().c_str());
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _position) {
+			_position = val;
+			what_changed = Change (what_changed | PositionChanged);
+		}
 	} else {
 		warning << _("old-style crossfade information - no position information") << endmsg;
 		_position = _in->first_frame();
 	}
 
 	if ((prop = node.property ("active")) != 0) {
-		_active = (prop->value() == "yes");
+		bool x = (prop->value() == "yes");
+		if (x != _active) {
+			_active = x;
+			what_changed = Change (what_changed | ActiveChanged);
+		}
 	} else {
 		_active = true;
 	}
@@ -767,7 +696,11 @@ Crossfade::set_state (const XMLNode& node)
 
 	if ((prop = node.property ("length")) != 0) {
 
-		_length = atol (prop->value().c_str());
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _length) {
+			_length = atol (prop->value().c_str());
+			what_changed = Change (what_changed | LengthChanged);
+		}
 
 	} else {
 		
@@ -790,6 +723,7 @@ Crossfade::set_state (const XMLNode& node)
 
 	/* fade in */
 	
+	_fade_in.freeze ();
 	_fade_in.clear ();
 	
 	children = fi->children();
@@ -808,9 +742,12 @@ Crossfade::set_state (const XMLNode& node)
 			_fade_in.add (x, y);
 		}
 	}
+
+	_fade_in.thaw ();
 	
         /* fade out */
 	
+	_fade_in.freeze ();
 	_fade_out.clear ();
 
 	children = fo->children();
@@ -831,6 +768,10 @@ Crossfade::set_state (const XMLNode& node)
 		}
 	}
 
+	_fade_out.thaw ();
+
+	StateChanged (what_changed); /* EMIT SIGNAL */
+
 	return 0;
 }
 
@@ -887,9 +828,7 @@ Crossfade::set_length (nframes_t len)
 	
 	_length = len;
 
-	save_state ("length changed");
-
-	send_state_changed (LengthChanged);
+	StateChanged (LengthChanged);
 
 	return len;
 }
diff --git a/libs/ardour/diskstream.cc b/libs/ardour/diskstream.cc
index f9fb540099..9e83c5e21a 100644
--- a/libs/ardour/diskstream.cc
+++ b/libs/ardour/diskstream.cc
@@ -331,7 +331,6 @@ Diskstream::use_playlist (Playlist* playlist)
 			reset_write_sources (false);
 		}
 		
-		plstate_connection = _playlist->StateChanged.connect (mem_fun (*this, &Diskstream::playlist_changed));
 		plmod_connection = _playlist->Modified.connect (mem_fun (*this, &Diskstream::playlist_modified));
 		plgone_connection = _playlist->GoingAway.connect (bind (mem_fun (*this, &Diskstream::playlist_deleted), _playlist));
 	}
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index 3ef817cc55..f87a30c931 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -117,7 +117,6 @@ Playlist::Playlist (const Playlist& other, string namestr, bool hide)
 	subcnt = 0;
 	_read_data_count = 0;
 	_frozen = other._frozen;
-	save_on_thaw = false;
 	
 	layer_op_counter = other.layer_op_counter;
 	freeze_length = other.freeze_length;
@@ -238,7 +237,6 @@ Playlist::init (bool hide)
 	subcnt = 0;
 	_read_data_count = 0;
 	_frozen = false;
-	save_on_thaw = false;
 	layer_op_counter = 0;
 	freeze_length = 0;
 
@@ -333,9 +331,9 @@ void
 Playlist::notify_region_removed (boost::shared_ptr<Region> r)
 {
 	if (holding_state ()) {
-		pending_removals.insert (pending_removals.end(), r);
+		pending_modified = true;
+		pending_length = true;
 	} else {
-		RegionRemoved (r); /* EMIT SIGNAL */
 		/* this might not be true, but we have to act
 		   as though it could be.
 		*/
@@ -347,13 +345,14 @@ Playlist::notify_region_removed (boost::shared_ptr<Region> r)
 void
 Playlist::notify_region_added (boost::shared_ptr<Region> r)
 {
+	/* the length change might not be true, but we have to act
+	   as though it could be.
+	*/
+
 	if (holding_state()) {
-		pending_adds.insert (pending_adds.end(), r);
+		pending_modified = true;
+		pending_length = true;
 	} else {
-		RegionAdded (r); /* EMIT SIGNAL */
-		/* this might not be true, but we have to act
-		   as though it could be.
-		*/
 		LengthChanged (); /* EMIT SIGNAL */
 		Modified (); /* EMIT SIGNAL */
 	}
@@ -406,22 +405,10 @@ Playlist::flush_notifications ()
 		/* don't increment n again - its the same list */
 	}
 
-	for (a = pending_adds.begin(); a != pending_adds.end(); ++a) {
-		dependent_checks_needed.insert (*a);
-		RegionAdded (*a); /* EMIT SIGNAL */
-		n++;
-	}
-
 	for (set<boost::shared_ptr<Region> >::iterator x = dependent_checks_needed.begin(); x != dependent_checks_needed.end(); ++x) {
 		check_dependents (*x, false);
 	}
 
-	for (r = pending_removals.begin(); r != pending_removals.end(); ++r) {
-		remove_dependents (*r);
-		RegionRemoved (*r); /* EMIT SIGNAL */
-		n++;
-	}
-
 	if ((freeze_length != _get_maximum_extent()) || pending_length) {
 		pending_length = 0;
 		LengthChanged(); /* EMIT SIGNAL */
@@ -437,15 +424,8 @@ Playlist::flush_notifications ()
 		Modified (); /* EMIT SIGNAL */
 	}
 
-	pending_adds.clear ();
-	pending_removals.clear ();
 	pending_bounds.clear ();
 
-	if (save_on_thaw) {
-		save_on_thaw = false;
-		save_state (last_save_reason);
-	}
-	
 	in_flush = false;
 }
 
@@ -454,7 +434,7 @@ Playlist::flush_notifications ()
  *************************************************************/
 
 void
-Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, float times, bool with_save) 
+Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, float times) 
 { 
 	RegionLock rlock (this);
 	
@@ -493,10 +473,6 @@ Playlist::add_region (boost::shared_ptr<Region> region, nframes_t position, floa
 		boost::shared_ptr<Region> sub = RegionFactory::create (region, 0, length, name, region->layer(), region->flags());
 		add_region_internal (sub, pos, true);
 	}
-	
-	if (with_save) {
-		maybe_save_state (_("add region"));
-	}
 }
 
 void
@@ -515,6 +491,7 @@ Playlist::add_region_internal (boost::shared_ptr<Region> region, nframes_t posit
 	timestamp_layer_op (region);
 
 	regions.insert (upper_bound (regions.begin(), regions.end(), region, cmp), region);
+	all_regions.insert (region);
 
 	if (!holding_state () && !in_set_state) {
 		/* layers get assigned from XML state */
@@ -547,8 +524,6 @@ Playlist::replace_region (boost::shared_ptr<Region> old, boost::shared_ptr<Regio
 	if (!holding_state ()) {
 		possibly_splice_unlocked ();
 	}
-
-	maybe_save_state (_("replace region"));
 }
 
 void
@@ -560,8 +535,6 @@ Playlist::remove_region (boost::shared_ptr<Region> region)
 	if (!holding_state ()) {
 		possibly_splice_unlocked ();
 	}
-
-	maybe_save_state (_("remove region"));
 }
 
 int
@@ -632,8 +605,6 @@ Playlist::partition (nframes_t start, nframes_t end, bool just_top_level)
 	for (RegionList::iterator i = thawlist.begin(); i != thawlist.end(); ++i) {
 		(*i)->thaw ("separation");
 	}
-
-	maybe_save_state (_("separate"));
 }
 
 void
@@ -897,8 +868,6 @@ Playlist::cut (nframes_t start, nframes_t cnt, bool result_is_hidden)
 		(*i)->thaw ("playlist cut");
 	}
 
-	maybe_save_state (_("cut"));
-
 	return the_copy;
 }
 
@@ -958,8 +927,6 @@ Playlist::paste (Playlist& other, nframes_t position, float times)
 		
 	}
 
-	maybe_save_state (_("paste"));
-
 	return 0;
 }
 
@@ -986,8 +953,6 @@ Playlist::duplicate (boost::shared_ptr<Region> region, nframes_t position, float
 		boost::shared_ptr<Region> sub = RegionFactory::create (region, 0, length, name, region->layer(), region->flags());
 		add_region_internal (sub, pos, true);
 	}
-
-	maybe_save_state (_("duplicate"));
 }
 
 void
@@ -1041,8 +1006,6 @@ Playlist::split_region (boost::shared_ptr<Region> region, nframes_t playlist_pos
 	if (remove_region_internal (region, true)) {
 		return;
 	}
-
-	maybe_save_state (_("split"));
 }
 
 void
@@ -1192,7 +1155,7 @@ Playlist::region_changed (Change what_changed, boost::shared_ptr<Region> region)
 }
 
 void
-Playlist::clear (bool with_save)
+Playlist::clear ()
 {
 	RegionList::iterator i;
 	RegionList tmp;
@@ -1206,10 +1169,6 @@ Playlist::clear (bool with_save)
 	for (i = tmp.begin(); i != tmp.end(); ++i) {
 		notify_region_removed (*i);
 	}
-
-	if (with_save) {
-		maybe_save_state (_("clear"));
-	}
 }
 
 /***********************************************************************
@@ -1339,8 +1298,6 @@ Playlist::mark_session_dirty ()
 int
 Playlist::set_state (const XMLNode& node)
 {
-	in_set_state = true;
-
 	XMLNode *child;
 	XMLNodeList nlist;
 	XMLNodeConstIterator niter;
@@ -1350,13 +1307,15 @@ Playlist::set_state (const XMLNode& node)
 	boost::shared_ptr<Region> region;
 	string region_name;
 
-	clear (false);
+	in_set_state = true;
 
 	if (node.name() != "Playlist") {
 		in_set_state = false;
 		return -1;
 	}
 
+	freeze ();
+
 	plist = node.properties();
 
 	for (piter = plist.begin(); piter != plist.end(); ++piter) {
@@ -1372,6 +1331,11 @@ Playlist::set_state (const XMLNode& node)
 		}
 	}
 
+	{ 
+		RegionLock rl (this);
+		regions.clear ();
+	}
+	
 	nlist = node.children();
 
 	for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
@@ -1385,19 +1349,29 @@ Playlist::set_state (const XMLNode& node)
 				continue;
 			}
 			
-			if ((region = RegionFactory::create (_session, *child, true)) == 0) {
-				error << _("Playlist: cannot create region from state file") << endmsg;
+			ID id = prop->value ();
+			
+			if ((region = region_by_id (id))) {
+
+				Change what_changed = Change (0);
+
+				if (region->set_live_state (*child, what_changed, true)) {
+					error << _("Playlist: cannot reset region state from XML") << endmsg;
+					continue;
+				}
+
+			} else if ((region = RegionFactory::create (_session, *child, true)) == 0) {
+				error << _("Playlist: cannot create region from XML") << endmsg;
 				continue;
 			}
 
-			add_region (region, region->position(), 1.0, false);
+			add_region (region, region->position(), 1.0);
 
 			// So that layer_op ordering doesn't get screwed up
 			region->set_last_layer_op( region->layer());
 
 		} 			
 	}
-
 	
  	/* update dependents, which was not done during add_region_internal 
 	   due to in_set_state being true 
@@ -1406,9 +1380,13 @@ Playlist::set_state (const XMLNode& node)
 	for (RegionList::iterator r = regions.begin(); r != regions.end(); ++r) {
 		check_dependents (*r, false);
 	}
-	
+
+	notify_modified ();
+
 	in_set_state = false;
 
+	thaw ();
+
 	return 0;
 }
 
@@ -1746,7 +1724,6 @@ Playlist::nudge_after (nframes_t start, nframes_t distance, bool forwards)
 
 	if (moved) {
 		_nudging = false;
-		maybe_save_state (_("nudged"));
 		notify_length_changed ();
 	}
 
@@ -1756,26 +1733,31 @@ boost::shared_ptr<Region>
 Playlist::find_region (const ID& id) const
 {
 	RegionLock rlock (const_cast<Playlist*> (this));
-	RegionList::const_iterator i;
-	boost::shared_ptr<Region> ret;
 
-	for (i = regions.begin(); i != regions.end(); ++i) {
+	/* searches all regions currently in use by the playlist */
+
+	for (RegionList::const_iterator i = regions.begin(); i != regions.end(); ++i) {
 		if ((*i)->id() == id) {
-			ret = *i;
+			return *i;
 		}
 	}
 
-	return ret;
+	return boost::shared_ptr<Region> ();
 }
-	
-void
-Playlist::save_state (std::string why)
+
+boost::shared_ptr<Region>
+Playlist::region_by_id (ID id)
 {
-	if (!in_set_state) {
-		StateManager::save_state (why);
+	/* searches all regions ever added to this playlist */
+
+	for (set<boost::shared_ptr<Region> >::iterator i = all_regions.begin(); i != all_regions.end(); ++i) {
+		if ((*i)->id() == id) {
+			return *i;
+		}
 	}
+	return boost::shared_ptr<Region> ();
 }
-
+	
 void
 Playlist::dump () const
 {
@@ -1811,13 +1793,3 @@ Playlist::timestamp_layer_op (boost::shared_ptr<Region> region)
 	region->set_last_layer_op (++layer_op_counter);
 }
 
-void
-Playlist::maybe_save_state (string why)
-{
-	if (holding_state ()) {
-		save_on_thaw = true;
-		last_save_reason = why;
-	} else {
-		save_state (why);
-	}
-}
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index ccdf3bdb5d..3a31fe254c 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -64,7 +64,6 @@ Region::Region (nframes_t start, nframes_t length, const string& name, layer_t l
 	_length = length; 
 	_position = 0; 
 	_layer = layer;
-	_current_state_id = 0;
 	_read_data_count = 0;
 	_first_edit = EditChangesNothing;
 	_last_layer_op = 0;
@@ -90,7 +89,6 @@ Region::Region (boost::shared_ptr<const Region> other, nframes_t offset, nframes
 	_position = 0; 
 	_layer = layer; 
 	_flags = Flag (flags & ~(Locked|WholeFile|Hidden));
-	_current_state_id = 0;
 	_first_edit = EditChangesNothing;
 	_last_layer_op = 0;
 }
@@ -120,7 +118,6 @@ Region::Region (boost::shared_ptr<const Region> other)
 	_position = other->_position; 
 	_layer = other->_layer; 
 	_flags = Flag (other->_flags & ~Locked);
-	_current_state_id = 0;
 	_last_layer_op = other->_last_layer_op;
 }
 
@@ -137,7 +134,6 @@ Region::Region (const XMLNode& node)
 	_position = 0; 
 	_layer = 0;
 	_flags = Flag (0);
-	_current_state_id = 0;
 	_first_edit = EditChangesNothing;
 
 	if (set_state (node)) {
@@ -157,69 +153,7 @@ Region::set_playlist (Playlist* pl)
 }
 
 void
-Region::store_state (RegionState& state) const
-{
-	state._start = _start;
-	state._length = _length;
-	state._position = _position;
-	state._flags = _flags;
-	state._sync_position = _sync_position;
-	state._layer = _layer;
-	state._name = _name;
-	state._first_edit = _first_edit;
-}	
-
-Change
-Region::restore_and_return_flags (RegionState& state)
-{
-	Change what_changed = Change (0);
-
-	{
-		Glib::Mutex::Lock lm (lock);
-		
-		if (_start != state._start) {
-			what_changed = Change (what_changed|StartChanged);	
-			_start = state._start;
-		}
-		if (_length != state._length) {
-			what_changed = Change (what_changed|LengthChanged);
-			_length = state._length;
-		}
-		if (_position != state._position) {
-			what_changed = Change (what_changed|PositionChanged);
-			_position = state._position;
-		} 
-		if (_sync_position != state._sync_position) {
-			_sync_position = state._sync_position;
-			what_changed = Change (what_changed|SyncOffsetChanged);
-		}
-		if (_layer != state._layer) {
-			what_changed = Change (what_changed|LayerChanged);
-			_layer = state._layer;
-		}
-
-		uint32_t old_flags = _flags;
-		_flags = Flag (state._flags);
-		
-		if ((old_flags ^ state._flags) & Muted) {
-			what_changed = Change (what_changed|MuteChanged);
-		}
-		if ((old_flags ^ state._flags) & Opaque) {
-			what_changed = Change (what_changed|OpacityChanged);
-		}
-		if ((old_flags ^ state._flags) & Locked) {
-			what_changed = Change (what_changed|LockChanged);
-		}
-
-		_first_edit = state._first_edit;
-	}
-
-	return what_changed;
-}
-
-void
 Region::set_name (string str)
-
 {
 	if (_name != str) {
 		_name = str; 
@@ -257,10 +191,6 @@ Region::set_length (nframes_t len, void *src)
 
 		if (!_frozen) {
 			recompute_at_end ();
-
-			char buf[64];
-			snprintf (buf, sizeof (buf), "length set to %u", len);
-			save_state (buf);
 		}
 
 		send_change (LengthChanged);
@@ -328,12 +258,6 @@ Region::set_position (nframes_t pos, void *src)
 		if (max_frames - _length < _position) {
 			_length = max_frames - _position;
 		}
-
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "position set to %u", pos);
-			save_state (buf);
-		}
 	}
 
 	/* do this even if the position is the same. this helps out
@@ -352,12 +276,6 @@ Region::set_position_on_top (nframes_t pos, void *src)
 
 	if (_position != pos) {
 		_position = pos;
-
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "position set to %u", pos);
-			save_state (buf);
-		}
 	}
 
 	_playlist->raise_region_to_top (boost::shared_ptr<Region>(this));
@@ -394,12 +312,6 @@ Region::nudge_position (long n, void *src)
 		}
 	}
 
-	if (!_frozen) {
-		char buf[64];
-		snprintf (buf, sizeof (buf), "position set to %u", _position);
-		save_state (buf);
-	}
-
 	send_change (PositionChanged);
 }
 
@@ -424,12 +336,6 @@ Region::set_start (nframes_t pos, void *src)
 		_flags = Region::Flag (_flags & ~WholeFile);
 		first_edit ();
 
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "start set to %u", pos);
-			save_state (buf);
-		}
-
 		send_change (StartChanged);
 	}
 }
@@ -480,12 +386,6 @@ Region::trim_start (nframes_t new_position, void *src)
 	_flags = Region::Flag (_flags & ~WholeFile);
 	first_edit ();
 
-	if (!_frozen) {
-		char buf[64];
-		snprintf (buf, sizeof (buf), "slipped start to %u", _start);
-		save_state (buf);
-	}
-
 	send_change (StartChanged);
 }
 
@@ -619,13 +519,6 @@ Region::trim_to_internal (nframes_t position, nframes_t length, void *src)
 	} 
 
 	if (what_changed) {
-		
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "trimmed to %u-%u", _position, _position+_length-1);
-			save_state (buf);
-		}
-
 		send_change (what_changed);
 	}
 }	
@@ -656,16 +549,6 @@ Region::set_muted (bool yn)
 			_flags = Flag (_flags & ~Muted);
 		}
 
-		if (!_frozen) {
-			char buf[64];
-			if (yn) {
-				snprintf (buf, sizeof (buf), "muted");
-			} else {
-				snprintf (buf, sizeof (buf), "unmuted");
-			}
-			save_state (buf);
-		}
-
 		send_change (MuteChanged);
 	}
 }
@@ -674,16 +557,10 @@ void
 Region::set_opaque (bool yn)
 {
 	if (opaque() != yn) {
-		if (!_frozen) {
-			char buf[64];
-			if (yn) {
-				snprintf (buf, sizeof (buf), "opaque");
-				_flags = Flag (_flags|Opaque);
-			} else {
-				snprintf (buf, sizeof (buf), "translucent");
-				_flags = Flag (_flags & ~Opaque);
-			}
-			save_state (buf);
+		if (yn) {
+			_flags = Flag (_flags|Opaque);
+		} else {
+			_flags = Flag (_flags & ~Opaque);
 		}
 		send_change (OpacityChanged);
 	}
@@ -693,16 +570,10 @@ void
 Region::set_locked (bool yn)
 {
 	if (locked() != yn) {
-		if (!_frozen) {
-			char buf[64];
-			if (yn) {
-				snprintf (buf, sizeof (buf), "locked");
-				_flags = Flag (_flags|Locked);
-			} else {
-				snprintf (buf, sizeof (buf), "unlocked");
-				_flags = Flag (_flags & ~Locked);
-			}
-			save_state (buf);
+		if (yn) {
+			_flags = Flag (_flags|Locked);
+		} else {
+			_flags = Flag (_flags & ~Locked);
 		}
 		send_change (LockChanged);
 	}
@@ -721,10 +592,7 @@ Region::set_sync_position (nframes_t absolute_pos)
 		_flags = Flag (_flags|SyncMarked);
 
 		if (!_frozen) {
-			char buf[64];
 			maybe_uncopy ();
-			snprintf (buf, sizeof (buf), "sync point set to %u", _sync_position);
-			save_state (buf);
 		}
 		send_change (SyncOffsetChanged);
 	}
@@ -738,7 +606,6 @@ Region::clear_sync_position ()
 
 		if (!_frozen) {
 			maybe_uncopy ();
-			save_state ("sync point removed");
 		}
 		send_change (SyncOffsetChanged);
 	}
@@ -842,12 +709,6 @@ Region::set_layer (layer_t l)
 	if (_layer != l) {
 		_layer = l;
 		
-		if (!_frozen) {
-			char buf[64];
-			snprintf (buf, sizeof (buf), "layer set to %" PRIu32, _layer);
-			save_state (buf);
-		}
-		
 		send_change (LayerChanged);
 	}
 }
@@ -857,7 +718,8 @@ Region::state (bool full_state)
 {
 	XMLNode *node = new XMLNode ("Region");
 	char buf[64];
-	
+	char* fe;
+
 	_id.print (buf, sizeof (buf));
 	node->add_property ("id", buf);
 	node->add_property ("name", _name);
@@ -867,6 +729,20 @@ Region::state (bool full_state)
 	node->add_property ("length", buf);
 	snprintf (buf, sizeof (buf), "%u", _position);
 	node->add_property ("position", buf);
+	
+	switch (_first_edit) {
+	case EditChangesNothing:
+		fe = X_("nothing");
+		break;
+	case EditChangesName:
+		fe = X_("name");
+		break;
+	case EditChangesID:
+		fe = X_("id");
+		break;
+	}
+
+	node->add_property ("first_edit", fe);
 
 	/* note: flags are stored by derived classes */
 
@@ -885,54 +761,83 @@ Region::get_state ()
 }
 
 int
-Region::set_state (const XMLNode& node)
+Region::set_live_state (const XMLNode& node, Change& what_changed, bool send)
 {
 	const XMLNodeList& nlist = node.children();
 	const XMLProperty *prop;
+	nframes_t val;
 
-	if (_extra_xml) {
-		delete _extra_xml;
-		_extra_xml = 0;
-	}
-
-	if ((prop = node.property ("id")) == 0) {
-		error << _("Session: XMLNode describing a Region is incomplete (no id)") << endmsg;
-		return -1;
-	}
-
-	_id = prop->value();
+	/* this is responsible for setting those aspects of Region state 
+	   that are mutable after construction.
+	*/
 
 	if ((prop = node.property ("name")) == 0) {
-		error << _("Session: XMLNode describing a Region is incomplete (no name)") << endmsg;
+		error << _("XMLNode describing a Region is incomplete (no name)") << endmsg;
 		return -1;
 	}
 
 	_name = prop->value();
 
 	if ((prop = node.property ("start")) != 0) {
-		sscanf (prop->value().c_str(), "%" PRIu32, &_start);
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _start) {
+			what_changed = Change (what_changed|StartChanged);	
+			_start = val;
+		}
+	} else {
+		_start = 0;
 	}
 
 	if ((prop = node.property ("length")) != 0) {
-		sscanf (prop->value().c_str(), "%" PRIu32, &_length);
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _length) {
+			what_changed = Change (what_changed|LengthChanged);
+			_length = val;
+		}
+	} else {
+		_length = 1;
 	}
 
 	if ((prop = node.property ("position")) != 0) {
-		sscanf (prop->value().c_str(), "%" PRIu32, &_position);
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _position) {
+			what_changed = Change (what_changed|PositionChanged);
+			_position = val;
+		}
+	} else {
+		_position = 0;
 	}
 
 	if ((prop = node.property ("layer")) != 0) {
-		_layer = (layer_t) atoi (prop->value().c_str());
+		layer_t x;
+		x = (layer_t) atoi (prop->value().c_str());
+		if (x != _layer) {
+			what_changed = Change (what_changed|LayerChanged);
+			_layer = x;
+		}
+	} else {
+		_layer = 0;
 	}
 
-	/* note: derived classes set flags */
-
 	if ((prop = node.property ("sync-position")) != 0) {
-		sscanf (prop->value().c_str(), "%" PRIu32, &_sync_position);
+		sscanf (prop->value().c_str(), "%" PRIu32, &val);
+		if (val != _sync_position) {
+			what_changed = Change (what_changed|SyncOffsetChanged);
+			_sync_position = val;
+		}
 	} else {
 		_sync_position = _start;
 	}
+
+	/* XXX FIRST EDIT !!! */
 	
+	/* note: derived classes set flags */
+
+	if (_extra_xml) {
+		delete _extra_xml;
+		_extra_xml = 0;
+	}
+
 	for (XMLNodeConstIterator niter = nlist.begin(); niter != nlist.end(); ++niter) {
 		
 		XMLNode *child;
@@ -945,7 +850,31 @@ Region::set_state (const XMLNode& node)
 		}
 	}
 
+	if (send) {
+		send_change (what_changed);
+	}
+
+	return 0;
+}
+
+int
+Region::set_state (const XMLNode& node)
+{
+	const XMLProperty *prop;
+	Change what_changed = Change (0);
+
+	/* ID is not allowed to change, ever */
+
+	if ((prop = node.property ("id")) == 0) {
+		error << _("Session: XMLNode describing a Region is incomplete (no id)") << endmsg;
+		return -1;
+	}
+
+	_id = prop->value();
+	
 	_first_edit = EditChangesNothing;
+	
+	set_live_state (node, what_changed, true);
 
 	return 0;
 }
@@ -985,7 +914,6 @@ Region::thaw (const string& why)
 		recompute_at_end ();
 	}
 		
-	save_state (why);
 	StateChanged (what_changed);
 }
 
@@ -1000,7 +928,7 @@ Region::send_change (Change what_changed)
 		} 
 	}
 
-	StateManager::send_state_changed (what_changed);
+	StateChanged (what_changed);
 }
 
 void
diff --git a/libs/ardour/session_command.cc b/libs/ardour/session_command.cc
index b54e5c8398..c5c31b7c17 100644
--- a/libs/ardour/session_command.cc
+++ b/libs/ardour/session_command.cc
@@ -28,22 +28,23 @@ Command *Session::memento_command_factory(XMLNode *n)
     id = PBD::ID(n->property("obj_id")->value());
 
     /* get before/after */
-    if (n->name() == "MementoCommand")
-    {
-        before = new XMLNode(*n->children().front());
-        after = new XMLNode(*n->children().back());
-	child = before;
-    } else if (n->name() == "MementoUndoCommand")
-    {
-        before = new XMLNode(*n->children().front());
-	child = before;
-    }
-    else if (n->name() == "MementoRedoCommand")
-    {
-        after = new XMLNode(*n->children().front());
-	child = after;
-    }
 
+    if (n->name() == "MementoCommand") {
+	    before = new XMLNode(*n->children().front());
+	    after = new XMLNode(*n->children().back());
+	    child = before;
+    } else if (n->name() == "MementoUndoCommand") {
+	    before = new XMLNode(*n->children().front());
+	    child = before;
+    } else if (n->name() == "MementoRedoCommand") {
+	    after = new XMLNode(*n->children().front());
+	    child = after;
+    } else if (n->name() == "PlaylistCommand") {
+	    before = new XMLNode(*n->children().front());
+	    after = new XMLNode(*n->children().back());
+	    child = before;
+    }
+		    
     if (!child)
     {
 	error << _("Tried to reconstitute a MementoCommand with no contents, failing. id=") << id.to_s() << endmsg;
@@ -53,43 +54,32 @@ Command *Session::memento_command_factory(XMLNode *n)
 
     /* create command */
     string obj_T = n->children().front()->name();
-    if (obj_T == "AudioRegion" || obj_T == "Region")
-    {
-        if (audio_regions.count(id))
-            return new MementoCommand<AudioRegion>(*audio_regions[id], before, after);
-    }
-    else if (obj_T == "AudioSource")
-    {
-        if (audio_sources.count(id))
-            return new MementoCommand<AudioSource>(*audio_sources[id], before, after);
-    }
-    else if (obj_T == "Location")
-        return new MementoCommand<Location>(*_locations.get_location_by_id(id), before, after);
-    else if (obj_T == "Locations")
-        return new MementoCommand<Locations>(_locations, before, after);
-    else if (obj_T == "TempoMap")
-        return new MementoCommand<TempoMap>(*_tempo_map, before, after);
-    else if (obj_T == "Playlist" || obj_T == "AudioPlaylist")
-    {
-        if (Playlist *pl = playlist_by_name(child->property("name")->value()))
-            return new MementoCommand<Playlist>(*pl, before, after);
-    }
-    else if (obj_T == "Route") // inlcudes AudioTrack
-        return new MementoCommand<Route>(*route_by_id(id), before, after);
-    else if (obj_T == "Curve")
-    {
-        if (curves.count(id))
-            return new MementoCommand<Curve>(*curves[id], before, after);
-    }
-    else if (obj_T == "AutomationList")
-    {
-        if (automation_lists.count(id))
-            return new MementoCommand<AutomationList>(*automation_lists[id], before, after);
+    if (obj_T == "AudioRegion" || obj_T == "Region") {
+	    if (audio_regions.count(id))
+		    return new MementoCommand<AudioRegion>(*audio_regions[id], before, after);
+    } else if (obj_T == "AudioSource") {
+	    if (audio_sources.count(id))
+		    return new MementoCommand<AudioSource>(*audio_sources[id], before, after);
+    } else if (obj_T == "Location") {
+	    return new MementoCommand<Location>(*_locations.get_location_by_id(id), before, after);
+    } else if (obj_T == "Locations") {
+	    return new MementoCommand<Locations>(_locations, before, after);
+    } else if (obj_T == "TempoMap") {
+	    return new MementoCommand<TempoMap>(*_tempo_map, before, after);
+    } else if (obj_T == "Playlist" || obj_T == "AudioPlaylist") {
+	    if (Playlist *pl = playlist_by_name(child->property("name")->value()))
+		    return new MementoCommand<Playlist>(*pl, before, after);
+    } else if (obj_T == "Route") { // includes AudioTrack
+	    return new MementoCommand<Route>(*route_by_id(id), before, after);
+    } else if (obj_T == "Curve") {
+	    if (curves.count(id))
+		    return new MementoCommand<Curve>(*curves[id], before, after);
+    } else if (obj_T == "AutomationList") {
+	    if (automation_lists.count(id))
+		    return new MementoCommand<AutomationList>(*automation_lists[id], before, after);
+    } else if (registry.count(id)) { // For Editor and AutomationLine which are off-limits here
+	    return new MementoCommand<StatefulDestructible>(*registry[id], before, after);
     }
-    // For Editor and AutomationLine which are off-limits here
-    else if (registry.count(id))
-        return new MementoCommand<StatefulDestructible>(*registry[id], before, after);
-
 
     /* we failed */
     error << _("could not reconstitute MementoCommand from XMLNode. id=") << id.to_s() << endmsg;
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 3c51bbfaf8..c3e0fe9388 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -2434,13 +2434,7 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 		delete *x;
 	}
 
-	/* step 2: clear the undo/redo history for all playlists */
-
-	for (PlaylistList::iterator x = playlists.begin(); x != playlists.end(); ++x) {
-		(*x)->drop_all_states ();
-	}
-
-	/* step 3: find all un-referenced sources */
+	/* step 2: find all un-referenced sources */
 
 	rep.paths.clear ();
 	rep.space = 0;
@@ -2470,7 +2464,7 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 		i = tmp;
 	}
 
-	/* Step 4: get rid of all regions in the region list that use any dead sources
+	/* Step 3: get rid of all regions in the region list that use any dead sources
 	   in case the sources themselves don't go away (they might be referenced in
 	   other snapshots).
 	*/
@@ -2863,41 +2857,39 @@ Session::restore_history (string snapshot_name)
 
     /* replace history */
     history.clear();
-    for (XMLNodeConstIterator it  = tree.root()->children().begin();
-         it != tree.root()->children().end();
-         it++)
-    {
-        XMLNode *t = *it;
-        UndoTransaction* ut = new UndoTransaction ();
-        struct timeval tv;
-
-        ut->set_name(t->property("name")->value());
-        stringstream ss(t->property("tv_sec")->value());
-        ss >> tv.tv_sec;
-        ss.str(t->property("tv_usec")->value());
-        ss >> tv.tv_usec;
-        ut->set_timestamp(tv);
-
-        for (XMLNodeConstIterator child_it  = t->children().begin();
-             child_it != t->children().end();
-             child_it++)
-        {
-            XMLNode *n = *child_it;
-            Command *c;
-            if (n->name() == "MementoCommand" ||
-                n->name() == "MementoUndoCommand" ||
-                n->name() == "MementoRedoCommand")
-            {
-                c = memento_command_factory(n);
-                if (c)
-                    ut->add_command(c);
-            }
-            else
-            {
-                error << string_compose(_("Couldn't figure out how to make a Command out of a %1 XMLNode."), n->name()) << endmsg;
-            }
-        }
-        history.add(ut);
+
+    for (XMLNodeConstIterator it  = tree.root()->children().begin(); it != tree.root()->children().end(); it++) {
+	    
+	    XMLNode *t = *it;
+	    UndoTransaction* ut = new UndoTransaction ();
+	    struct timeval tv;
+	    
+	    ut->set_name(t->property("name")->value());
+	    stringstream ss(t->property("tv_sec")->value());
+	    ss >> tv.tv_sec;
+	    ss.str(t->property("tv_usec")->value());
+	    ss >> tv.tv_usec;
+	    ut->set_timestamp(tv);
+	    
+	    for (XMLNodeConstIterator child_it  = t->children().begin();
+		 child_it != t->children().end();
+		 child_it++)
+	    {
+		    XMLNode *n = *child_it;
+		    Command *c;
+	
+		    if (n->name() == "MementoCommand" ||
+			n->name() == "MementoUndoCommand" ||
+			n->name() == "MementoRedoCommand") {
+			    if ((c = memento_command_factory(n))) {
+				    ut->add_command(c);
+			    }
+		    } else {
+			    error << string_compose(_("Couldn't figure out how to make a Command out of a %1 XMLNode."), n->name()) << endmsg;
+		    }
+	    }
+
+	    history.add (ut);
     }
 
     return 0;