Fix regression in auibar introduced in commit e32ba711 which mistakenly reverted the fix introduced in commit e059ec1a

wx/lib/agw/aui/auibar.py

@@ -3257,6 +3257,9 @@ class AuiToolBar(wx.Control):
     def DoIdleUpdate(self):
         """ Updates the toolbar during idle times. """
 
+        if not self:
+            return # The action Destroyed the toolbar!
+
         handler = self.GetEventHandler()
         if not handler:
             return