diff --git a/Timeline/Audio_Sequence.C b/Timeline/Audio_Sequence.C
index 72d43a0..c5ae1b1 100644
--- a/Timeline/Audio_Sequence.C
+++ b/Timeline/Audio_Sequence.C
@@ -75,10 +75,10 @@ Audio_Sequence::capture_region ( void ) const
 
 void
 Audio_Sequence::get ( Log_Entry &e ) const
-        {
-            e.add( ":track", _track );
-            e.add( ":name", name() );
-        }
+{
+    e.add( ":track", _track );
+    e.add( ":name", name() );
+}
 
 void
 Audio_Sequence::set ( Log_Entry &e )
@@ -177,9 +177,9 @@ Audio_Sequence::draw ( void )
                 ++xfades;
 
                 Rectangle b( (*r)->x(),
-                               o->y(),
-                               (o->x() + o->w()) - (*r)->x(),
-                               o->h() );
+                             o->y(),
+                             (o->x() + o->w()) - (*r)->x(),
+                             o->h() );
 
                 Fl_Color c = fl_color_average( o->box_color(), (*r)->box_color(), 0.50f );
                 c = fl_color_average( c, FL_YELLOW, 0.30f );
diff --git a/Timeline/Loggable.C b/Timeline/Loggable.C
index 9a64bda..fa102f5 100644
--- a/Timeline/Loggable.C
+++ b/Timeline/Loggable.C
@@ -56,6 +56,9 @@ std::queue <char *> Loggable::_transaction;
 progress_func *Loggable::_progress_callback = NULL;
 void *Loggable::_progress_callback_arg = NULL;
 
+snapshot_func *Loggable::_snapshot_callback = NULL;
+void *Loggable::_snapshot_callback_arg = NULL;
+
 
 
 /** ensure that _loggables array is big enough for /n/ elements */
@@ -419,6 +422,12 @@ Loggable::snapshot ( FILE *fp )
 {
     FILE *ofp = _fp;
 
+    if ( ! Loggable::_snapshot_callback )
+    {
+        DWARNING( "No snapshot callback defined" );
+        return false;
+    }
+
     if ( ! ( _fp = fp ) )
     {
         _fp = ofp;
@@ -427,13 +436,7 @@ Loggable::snapshot ( FILE *fp )
 
     block_start();
 
-    for ( int i = 0; i < _log_id; ++i )
-    {
-        const Loggable * l = _loggables[ i ];
-
-        if ( l && _class_map[ std::string( l->class_name() ) ] )
-            l->log_create();
-    }
+    Loggable::_snapshot_callback( _snapshot_callback_arg );
 
     block_end();
 
diff --git a/Timeline/Loggable.H b/Timeline/Loggable.H
index f71d1b4..6da28d8 100644
--- a/Timeline/Loggable.H
+++ b/Timeline/Loggable.H
@@ -34,6 +34,7 @@
 #include "types.h"
 
 typedef void (progress_func)( int, void * );
+typedef void (snapshot_func)( void * );
 
 class Log_Entry;
 class Loggable;
@@ -79,6 +80,9 @@ class Loggable
     static progress_func *_progress_callback;
     static void *_progress_callback_arg;
 
+    static snapshot_func *_snapshot_callback;
+    static void *_snapshot_callback_arg;
+
 private:
 
     int _id;
@@ -124,6 +128,7 @@ private:
 
 public:
 
+    static void snapshot_callback ( snapshot_func *p, void *arg ) { _snapshot_callback = p; _snapshot_callback_arg = arg; }
     static void progress_callback ( progress_func *p, void *arg ) { _progress_callback = p; _progress_callback_arg = arg;}
     static const char *escape ( const char *s );
 
@@ -165,16 +170,17 @@ public:
 
     virtual const char *class_name ( void ) const = 0;
 
+    virtual void log_children ( void ) const { return; }
 
     static bool do_this ( const char *s, bool reverse );
 
+    void log_create  ( void ) const;
 
 protected:
 
     void log_start ( void );
     void log_end ( void );
 
-    void log_create  ( void ) const;
     void log_destroy ( void ) const;
 
     /* leaf subclasses *must* call log_create() at the end of their copy contructors */
diff --git a/Timeline/Sequence.C b/Timeline/Sequence.C
index 8c7c082..f87c1e9 100644
--- a/Timeline/Sequence.C
+++ b/Timeline/Sequence.C
@@ -85,23 +85,25 @@ Sequence::~Sequence (  )
 
 
 
+void
+Sequence::log_children ( void ) const
+{
+    if ( id() > 0 )
+        log_create();
+
+    for ( std::list <Sequence_Widget*>::const_iterator i = _widgets.begin();
+          i != _widgets.end(); ++i )
+        (*i)->log_create();
+}
+
 /** remove all widgets from this sequence */
 void
 Sequence::clear ( void )
 {
     Loggable::block_start();
 
-    for ( std::list <Sequence_Widget*>::iterator i = _widgets.begin();
-          i != _widgets.end(); ++i )
-    {
-        Sequence_Widget *w = *i;
-
-        *i = NULL;
-
-        delete w;
-    }
-
-    _widgets.clear();
+    while ( _widgets.size() )
+        delete _widgets.front();
 
     Loggable::block_end();
 }
@@ -137,6 +139,11 @@ Sequence::overlaps ( Sequence_Widget *r )
 void
 Sequence::handle_widget_change ( nframes_t start, nframes_t length )
 {
+    timeline->wrlock();
+
+    sort();
+
+    timeline->unlock();
 //    timeline->update_length( start + length );
 }
 
@@ -177,8 +184,6 @@ Sequence::add ( Sequence_Widget *r )
     r->sequence( this );
     _widgets.push_back( r );
 
-    sort();
-
     timeline->unlock();
 
     handle_widget_change( r->start(), r->length() );
diff --git a/Timeline/Sequence.H b/Timeline/Sequence.H
index 87aeb72..2133f2e 100644
--- a/Timeline/Sequence.H
+++ b/Timeline/Sequence.H
@@ -62,9 +62,10 @@ protected:
     Sequence_Widget *widget_at ( nframes_t ts, int Y );
     Sequence_Widget *event_widget ( void );
 
-
 public:
 
+    virtual void log_children ( void ) const;
+
     /* child classes should implement this if they need to take
      special action when a widget is changed/moved/resized. /start/
      and /length/ define the affected region */
diff --git a/Timeline/Sequence_Widget.C b/Timeline/Sequence_Widget.C
index 50adf57..eea2d87 100644
--- a/Timeline/Sequence_Widget.C
+++ b/Timeline/Sequence_Widget.C
@@ -135,7 +135,7 @@ Sequence_Widget::set ( Log_Entry &e )
             sscanf( v, "%X", &i );
             Sequence *t = (Sequence*)Loggable::find( i );
 
-            assert( t );
+            ASSERT( t, "No such object ID (%s)", v );
 
             t->add( this );
         }
@@ -144,8 +144,10 @@ Sequence_Widget::set ( Log_Entry &e )
     }
 
     if ( _sequence )
+    {
+        _sequence->handle_widget_change( _r->start, _r->length );
         _sequence->redraw();
-
+    }
 }
 
 void
diff --git a/Timeline/Tempo_Point.C b/Timeline/Tempo_Point.C
index 3a80fff..bac51c2 100644
--- a/Timeline/Tempo_Point.C
+++ b/Timeline/Tempo_Point.C
@@ -83,7 +83,11 @@ Tempo_Point::set ( Log_Entry &e )
     _make_label();
 }
 
-
+void
+Tempo_Point::log_children ( void ) const
+{
+    log_create();
+}
 
 int
 Tempo_Point::handle ( int m )
diff --git a/Timeline/Tempo_Point.H b/Timeline/Tempo_Point.H
index f8389dd..f3e4396 100644
--- a/Timeline/Tempo_Point.H
+++ b/Timeline/Tempo_Point.H
@@ -44,6 +44,7 @@ protected:
 
     virtual void get ( Log_Entry &e ) const;
     void set ( Log_Entry &e );
+    void log_children ( void ) const;
 
     Tempo_Point ( );
 
diff --git a/Timeline/Time_Point.C b/Timeline/Time_Point.C
index 1dd243d..f1c1ad1 100644
--- a/Timeline/Time_Point.C
+++ b/Timeline/Time_Point.C
@@ -93,6 +93,12 @@ Time_Point::set ( Log_Entry &e )
     _make_label();
 }
 
+void
+Time_Point::log_children ( void ) const
+{
+    log_create();
+}
+
 int
 Time_Point::handle ( int m )
 {
diff --git a/Timeline/Time_Point.H b/Timeline/Time_Point.H
index b589fc1..5d51337 100644
--- a/Timeline/Time_Point.H
+++ b/Timeline/Time_Point.H
@@ -57,6 +57,7 @@ protected:
 
     virtual void get ( Log_Entry &e ) const;
     void set ( Log_Entry &e );
+    void log_children ( void ) const;
 
     Time_Point ( );
 
diff --git a/Timeline/Timeline.C b/Timeline/Timeline.C
index faaa679..51e6b89 100644
--- a/Timeline/Timeline.C
+++ b/Timeline/Timeline.C
@@ -105,6 +105,20 @@ draw_full_arrow_symbol ( Fl_Color color )
 
 
 
+/** callback used by Loggable class to create a snapshot of system
+ * state. */
+void
+Timeline::snapshot ( void )
+{
+    tempo_track->log_children();
+    time_track->log_children();
+
+    for ( int i = 0; i < tracks->children(); ++i )
+    {
+        ((Track*)tracks->child( i ))->log_children();
+    }
+}
+
 /** recalculate the size of vertical scrolling area and inform scrollbar */
 void
 Timeline::adjust_vscroll ( void )
@@ -347,6 +361,8 @@ Timeline::ntracks ( void ) const
 
 Timeline::Timeline ( int X, int Y, int W, int H, const char* L ) : Fl_Overlay_Window( X, Y, W, H, L )
 {
+    Loggable::snapshot_callback( &Timeline::snapshot, this );
+
     _sample_rate = 0;
 
     box( FL_FLAT_BOX );
diff --git a/Timeline/Timeline.H b/Timeline/Timeline.H
index 73b15f2..ed68f5d 100644
--- a/Timeline/Timeline.H
+++ b/Timeline/Timeline.H
@@ -213,6 +213,9 @@ public:
 
 private:
 
+    static void snapshot ( void *v ) { ((Timeline*)v)->snapshot(); }
+    void snapshot ( void );
+
     friend class Engine; // FIXME: only Engine::process() needs to be friended.x
 
     Track * track_by_name ( const char *name );
diff --git a/Timeline/Track.C b/Timeline/Track.C
index be2547f..1a9b152 100644
--- a/Timeline/Track.C
+++ b/Timeline/Track.C
@@ -72,16 +72,6 @@ Track::Track ( ) : Fl_Group( 0, 0, 1, 1 )
     timeline->add_track( this );
 }
 
-void
-Track::solo ( bool b )
-{
-    if ( b && ! solo_button->value() )
-        ++_soloing;
-    else if ( ! b && solo_button->value() )
-        --_soloing;
-
-    solo_button->value( b );
-}
 
 Track::~Track ( )
 {
@@ -306,6 +296,33 @@ Track::get ( Log_Entry &e ) const
     e.add( ":show-all-takes",  _show_all_takes  );
 }
 
+void
+Track::log_children ( void ) const
+{
+    log_create();
+
+    for ( int i = control->children(); i--; )
+        ((Sequence*)control->child( i ))->log_children();
+
+    for ( int i = annotation->children(); i--; )
+        ((Sequence*)annotation->child( i ))->log_children();
+
+    for ( int i = takes->children(); i--; )
+        ((Sequence*)takes->child( i ))->log_children();
+
+    sequence()->log_children();
+}
+
+void
+Track::solo ( bool b )
+{
+    if ( b && ! solo_button->value() )
+        ++_soloing;
+    else if ( ! b && solo_button->value() )
+        --_soloing;
+
+    solo_button->value( b );
+}
 
 void
 Track::cb_input_field ( Fl_Widget *, void *v )
diff --git a/Timeline/Track.H b/Timeline/Track.H
index 678e5ad..060da3d 100644
--- a/Timeline/Track.H
+++ b/Timeline/Track.H
@@ -108,6 +108,8 @@ protected:
 
 public:
 
+    virtual void log_children ( void ) const;
+
     Fl_Input       *name_field;
     Fl_Button      *record_button;
     Fl_Button      *mute_button;