diff -r fdb9501e5cc8 -r c487c54c1cfe PLCOpenEditor.py
--- a/PLCOpenEditor.py	Wed Dec 21 19:38:26 2011 +0100
+++ b/PLCOpenEditor.py	Wed Dec 21 19:41:29 2011 +0100
@@ -477,7 +477,7 @@
         
             self.TabsOpened = wx.aui.AuiNotebook(self, ID_PLCOPENEDITORTABSOPENED, 
                   style=wx.aui.AUI_NB_DEFAULT_STYLE|wx.aui.AUI_NB_WINDOWLIST_BUTTON)
-            self.TabsOpened.Bind(wx.aui.EVT_AUINOTEBOOK_PAGE_CHANGED,
+            self.TabsOpened.Bind(wx.aui.EVT_AUINOTEBOOK_PAGE_CHANGING,
                     self.OnPouSelectedChanged)
             self.TabsOpened.Bind(wx.aui.EVT_AUINOTEBOOK_PAGE_CLOSE,
                     self.OnPageClose)
@@ -519,10 +519,10 @@
                   0), size=wx.Size(0, 0), style=0)
             self.TabsOpened.SetImageList(self.TabsImageList)
             if wx.VERSION >= (2, 6, 0):
-                self.TabsOpened.Bind(wx.EVT_NOTEBOOK_PAGE_CHANGED,
+                self.TabsOpened.Bind(wx.EVT_NOTEBOOK_PAGE_CHANGING,
                     self.OnPouSelectedChanged, id=ID_PLCOPENEDITORTABSOPENED)
             else:
-                wx.EVT_NOTEBOOK_PAGE_CHANGED(self.TabsOpened, ID_PLCOPENEDITORTABSOPENED,
+                wx.EVT_NOTEBOOK_PAGE_CHANGING(self.TabsOpened, ID_PLCOPENEDITORTABSOPENED,
                     self.OnPouSelectedChanged)
             
             self.RightNoteBook = wx.Notebook(id=ID_PLCOPENEDITORRIGHTNOTEBOOK,
@@ -1002,7 +1002,7 @@
                 window = self.TabsOpened.GetPage(selected)
                 undo, redo = window.GetBufferState()
             else:
-                undo, redo = False, False
+                undo, redo = self.Controler.GetBufferState()
             self.EditMenu.Enable(wx.ID_UNDO, undo)
             self.EditMenu.Enable(wx.ID_REDO, redo)
             #self.EditMenu.Enable(ID_PLCOPENEDITOREDITMENUENABLEUNDOREDO, True)
@@ -1049,16 +1049,20 @@
         if selected != -1:
             window = self.TabsOpened.GetPage(selected)
             window.Undo()
-            self._Refresh(TITLE, FILEMENU, EDITMENU, TYPESTREE, INSTANCESTREE, LIBRARYTREE, 
-                          SCALING, PAGETITLES)
+        else:
+            self.Controler.LoadPrevious()
+        self._Refresh(TITLE, FILEMENU, EDITMENU, TYPESTREE, INSTANCESTREE, LIBRARYTREE, 
+                      SCALING, PAGETITLES)    
     
     def OnRedoMenu(self, event):
         selected = self.TabsOpened.GetSelection()
         if selected != -1:
             window = self.TabsOpened.GetPage(selected)
             window.Redo()
-            self._Refresh(TITLE, FILEMENU, EDITMENU, TYPESTREE, INSTANCESTREE, LIBRARYTREE, 
-                          SCALING, PAGETITLES)
+        else:
+            self.Controler.LoadNext()
+        self._Refresh(TITLE, FILEMENU, EDITMENU, TYPESTREE, INSTANCESTREE, LIBRARYTREE, 
+                      SCALING, PAGETITLES)
     
     def OnEnableUndoRedoMenu(self, event):
         self.Controler.EnableProjectBuffer(event.IsChecked())
@@ -1196,8 +1200,10 @@
         if selected >= 0:
             window = self.TabsOpened.GetPage(selected)
             if not window.IsDebugging():
+                print "Is not Debugging"
                 wx.CallAfter(self.SelectTypesTreeItem, window.GetTagName())
             else:
+                print "Is Debugging"
                 wx.CallAfter(self.SelectInstancesTreeItem, self.InstancesTree.GetRootItem(), window.GetInstancePath())
             window.RefreshView()
             self._Refresh(FILEMENU, EDITMENU, DISPLAYMENU, TOOLBAR)