diff --git a/src/gui/widgets/undoablebuffer.py b/src/gui/widgets/undoablebuffer.py
index 7093c2244..c8343056a 100644
--- a/src/gui/widgets/undoablebuffer.py
+++ b/src/gui/widgets/undoablebuffer.py
@@ -36,6 +36,7 @@ class Stack(list):
     """
     Very simple stack implementation that cannot grow beyond an at init 
     determined size. 
+    Inherits from list.
     Only append checks if this is really the case!
     """
     def __init__(self, stack_size=None):
@@ -108,7 +109,7 @@ class UndoableBuffer(gtk.TextBuffer):
     def can_redo(self):
         return bool(self.redo_stack)
 
-    def __empty_redo_stack(self):
+    def _empty_redo_stack(self):
         self.redo_stack = []
 
     def on_insert_text_undoable(self, textbuffer, text_iter, text, length):
@@ -131,7 +132,7 @@ class UndoableBuffer(gtk.TextBuffer):
             return True
 
         if not self.undo_in_progress:
-            self.__empty_redo_stack()
+            self._empty_redo_stack()
         if self.not_undoable_action:
             return
         undo_action = self.insertclass(text_iter, text, length, textbuffer)
@@ -177,7 +178,7 @@ class UndoableBuffer(gtk.TextBuffer):
             return True
 
         if not self.undo_in_progress:
-            self.__empty_redo_stack()
+            self._empty_redo_stack()
         if self.not_undoable_action:
             return
         undo_action = self.deleteclass(text_buffer, start_iter, end_iter)
diff --git a/src/gui/widgets/undoablestyledbuffer.py b/src/gui/widgets/undoablestyledbuffer.py
index 4e2401e6e..53a177c10 100644
--- a/src/gui/widgets/undoablestyledbuffer.py
+++ b/src/gui/widgets/undoablestyledbuffer.py
@@ -96,7 +96,7 @@ class UndoableStyledBuffer(StyledTextBuffer):
 
     def on_tag_insert_undoable(self, buffer, tag, start, end):
         if not self.undo_in_progress:
-            self.__empty_redo_stack()
+            self._empty_redo_stack()
         if self.not_undoable_action:
             return
         if end.get_offset() - start.get_offset() == 1: