There's no need to handle anything on timelines on those callbacks. The timeline can be usefull to get the frame number, the total number of frames etc... when the timeline is *playing* but those callbacks are called when the timeline is *completed*

the diff :
=== modified file 'entertainerlib/frontend/gui/screens/photoalbums_screen.py'
--- entertainerlib/frontend/gui/screens/photoalbums_screen.py	2008-12-14 22:46:36 +0000
+++ entertainerlib/frontend/gui/screens/photoalbums_screen.py	2009-01-06 11:01:42 +0000
@@ -236,10 +236,9 @@
     def _change_preview_timeline_ended(self, timeline, group):
         """
         This is a callback function for preview updates. This is called when
-        transition effect is finished. This mehtod removes old preview group
+        transition effect is finished. This method removes old preview group
         from the stage.
         """
-        # TODO: Figure out if/how timeline needs to be used
         self.remove(group)
 
     def _change_preview_image(self):

=== modified file 'entertainerlib/frontend/gui/transitions/fade_transition.py'
--- entertainerlib/frontend/gui/transitions/fade_transition.py	2008-10-07 22:59:41 +0000
+++ entertainerlib/frontend/gui/transitions/fade_transition.py	2009-01-06 11:01:42 +0000
@@ -70,11 +70,3 @@
         # Same effect. Direction doesn't make any difference
         self.forward_effect(from_screen, to_screen)
 
-    def _remove_from_stage_callback(self, timeline, screen):
-        """
-        Callback for fadeout timeline. This method is called when transition
-        direction is BACKWARDS. This method removes old screen from stage.
-        """
-        # TODO: Determine if timeline needs to be used somehow
-        self.stage.remove(screen)
-

=== modified file 'entertainerlib/frontend/gui/transitions/slide_and_fade_transition.py'
--- entertainerlib/frontend/gui/transitions/slide_and_fade_transition.py	2008-10-07 22:59:41 +0000
+++ entertainerlib/frontend/gui/transitions/slide_and_fade_transition.py	2009-01-06 11:01:42 +0000
@@ -162,11 +162,3 @@
         slide_out.start()
         slide_in.start()
 
-    def _remove_from_stage_callback(self, timeline, screen):
-        """
-        Callback for fadeout timeline. This method is called when transition
-        direction is BACKWARDS. This method removes old screen from stage.
-        """
-        # TODO: Figure out if timeline needs to be used somehow
-        self.stage.remove(screen)
-

=== modified file 'entertainerlib/frontend/gui/transitions/slide_transition.py'
--- entertainerlib/frontend/gui/transitions/slide_transition.py	2008-10-07 22:59:41 +0000
+++ entertainerlib/frontend/gui/transitions/slide_transition.py	2009-01-06 11:01:42 +0000
@@ -153,11 +153,3 @@
         slide_out.start()
         slide_in.start()
 
-    def _remove_from_stage_callback(self, timeline, screen):
-        """
-        Callback for fadeout timeline. This method is called when transition
-        direction is BACKWARDS. This method removes old screen from stage.
-        """
-        # TODO: Determine if timeline should be used.
-        self.stage.remove(screen)
-

=== modified file 'entertainerlib/frontend/gui/transitions/transition.py'
--- entertainerlib/frontend/gui/transitions/transition.py	2008-08-02 21:33:38 +0000
+++ entertainerlib/frontend/gui/transitions/transition.py	2009-01-06 11:01:42 +0000
@@ -47,3 +47,10 @@
         """
         pass
 
+    def _remove_from_stage_callback(self, timeline, screen):
+        """
+        Callback for fadeout timeline. This method is called when transition
+        direction is BACKWARDS. This method removes old screen from stage.
+        """
+        self.stage.remove(screen)
+

=== modified file 'entertainerlib/frontend/gui/transitions/zoom_and_fade_transition.py'
--- entertainerlib/frontend/gui/transitions/zoom_and_fade_transition.py	2008-10-07 22:59:41 +0000
+++ entertainerlib/frontend/gui/transitions/zoom_and_fade_transition.py	2009-01-06 11:01:42 +0000
@@ -105,11 +105,3 @@
             fade_out.start()
         fade_in.start()
 
-    def _remove_from_stage_callback(self, timeline, screen):
-        """
-        Callback for fadeout timeline. This method is called when transition
-        direction is BACKWARDS. This method removes old screen from stage.
-        """
-        # TODO: Determine if timeline should be used
-        self.stage.remove(screen)
-

Cheers,

Samuel