--- a/pyink/MBScene.py	Wed Jan 12 12:25:45 2011 +0800
+++ b/pyink/MBScene.py	Wed Jan 12 15:01:14 2011 +0800
@@ -70,6 +70,7 @@
 	self.current = 0
 
 	self._domviewui = create_domview_ui()
+	self._locker = self._domviewui
 	pass
 
     def change_active_frame(self, node):
@@ -255,6 +256,14 @@
 	self._lockui = False
 	return
 
+    def lock(self):
+        self._domviewui.lock()
+	pass
+
+    def unlock(self):
+        self._domviewui.unlock()
+	pass
+
     
     def doExtendScene(self,w):
 	self._lockui = True

--- a/pyink/consistency.py	Wed Jan 12 12:25:45 2011 +0800
+++ b/pyink/consistency.py	Wed Jan 12 15:01:14 2011 +0800
@@ -1,6 +1,6 @@
 import dom_event
 from data_monitor import data_monitor
-
+import traceback
 ## \brief Check consistency of a DOM-tree associated with a domview_ui.
 #
 # This is a co-worker of \ref domview_ui to check DOM-tree and make
@@ -26,6 +26,7 @@
     
     def __init__(self, domview_ui):
         self._domview = domview_ui
+	self._locker = self._domview
         self._doc = None
         self._root = None
         pass
@@ -75,6 +76,7 @@
         pass
 
     def _remove_node_recursive(self, node, child):
+    	return
         for cchild in child.childList():
             self._remove_node_recursive(child, cchild)
             pass
@@ -131,5 +133,22 @@
         pass
 
     def do_attr_modified(self, node, name, old_value, new_value):
+    	if node.name() == 'ns0:scene' and name == 'ref':
+	    try:
+	        if new_value:
+		    raise ValueError('The new_value is not empty')
+	        self._domview.reset()
+	    except:
+	        traceback.print_exc()
+	        pass
+	    pass
         pass
     pass
+
+    def lock(self):
+        self._domview.lock()
+	pass
+
+    def unlock(self):
+        self._domview.unlock()
+	pass

--- a/pyink/data_monitor.py	Wed Jan 12 12:25:45 2011 +0800
+++ b/pyink/data_monitor.py	Wed Jan 12 15:01:14 2011 +0800
@@ -34,7 +34,7 @@
 		    print '    kws:  %s' % (repr(kws))
 		    pass
 		
-		if not self._domview.lock(): # can not lock
+		if not self._locker.lock(): # can not lock
 		    if debug_level >= 1:
 			print '  fault to lock'
 			pass
@@ -43,7 +43,7 @@
 		try:
 		    func(self, *args, **kws)
 		finally:
-		    self._domview.unlock()
+		    self._locker.unlock()
 		    pass
 		pass
 	    return sentinel

--- a/pyink/domview.py	Wed Jan 12 12:25:45 2011 +0800
+++ b/pyink/domview.py	Wed Jan 12 15:01:14 2011 +0800
@@ -72,7 +72,7 @@
 	    except:
 		pass
 	    pass
-	pass
+	pass	    
 
     def _find_maxframe(self, scenes_node):
 	maxframe = 0
@@ -104,8 +104,7 @@
 	    pass
 	else:
 	    if child_id not in self._id2node:
-		raise ValueError, \
-		    'remove a node that is never known (%s)' % (child_id)
+	        return
 	    del self._id2node[child_id]
 	    pass
 	
@@ -189,7 +188,7 @@
     
     def _parse_one_scene(self, scene_node):
 	assert scene_node.name() == 'ns0:scene'
-	
+
 	start = int(scene_node.getAttribute("start"))
 	try:
 	    end = int(scene_node.getAttribute("end"))
@@ -221,6 +220,7 @@
 		continue
 
 	    try:
+	    	ref = scene_node.getAttribute('ref')
 		start, end, scene_type = self._parse_one_scene(scene_node)
 	    except:
 		continue
@@ -349,6 +349,10 @@
 	self._init_metadata()
 	self._parse_all_layers()
 	pass
+
+    def reset(self):
+        self.handle_doc_root( self._doc, self._root)
+	pass
    
     def dumpattr(self, n):
 	s = ""
@@ -665,6 +669,12 @@
 	    pass
 	pass
 
+    ## \brief add the current position to the undo buffer
+    #
+    def mark_undo(self, msg):
+    	self._doc.done("none", msg)
+    	pass
+
     ## \brief Remove frames
     #
     # - Scenes covered by removing range were removed.

--- a/pyink/domview_ui.py	Wed Jan 12 12:25:45 2011 +0800
+++ b/pyink/domview_ui.py	Wed Jan 12 15:01:14 2011 +0800
@@ -75,7 +75,6 @@
     def _add_frameline(self, layer_idx):
 	if layer_idx > len(self._framelines):
 	    raise ValueError, 'layer number should be a consequence'
-
 	vbox = self._frameline_vbox
 	
 	line = frameline(self._num_frames_of_line)
@@ -111,6 +110,7 @@
 	
 	hbox = line.parent
 	vbox.remove(hbox)
+	hbox.remove(line)
 	del self._framelines[layer_idx]
 	
 	for idx in range(layer_idx, len(self._framelines)):
@@ -118,7 +118,23 @@
 	    pass
 	pass
 
+    def _remove_all_framelines(self):
+        num = len(self._framelines)
+	
+        for idx in range(0,num):
+	    line = self._framelines[idx]
+	    hbox = line.parent
+	    self._frameline_vbox.remove(hbox)
+	self._framelines=[]
+	self._last_mouse_over_frameline = None
+	self._last_active_frameline = None
+	self._active_frame_callback = None
+
+	pass
+
     def _init_framelines(self):
+        if self._framelines!= None: 
+	    return
 	self._framelines = []
 	
 	box = gtk.ScrolledWindow()
@@ -411,6 +427,13 @@
         self._root = root
 	pass
 
+    ## \brief Reload the document.
+    #
+    def reset(self):
+        self._fl_stack._remove_all_framelines()
+        self.handle_doc_root(self._doc, self._root)
+	pass
+
     ## \brief Mark given frame as a key frame.
     #
     def mark_key(self, layer_idx, key_idx):
@@ -645,6 +668,13 @@
 	max_frame = self._dom.get_max_frame()
 	return max_frame
 
+    ## \brief add the current position to the undo buffer.
+    #
+    #  The msg will be displayed in the UI to indicate the undo set.
+    def mark_undo(self, msg):
+    	self._dom.mark_undo(msg)
+    	pass
+
     @property
     def doc(self):
         return self._doc