From 0ff3b4174525c81d0f42ac200261ecee4d3d581f Mon Sep 17 00:00:00 2001
From: Damien Elmes <git@ichi2.net>
Date: Mon, 1 Dec 2008 00:17:43 +0900
Subject: [PATCH] don't add layers of undo barriers

---
 anki/deck.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/anki/deck.py b/anki/deck.py
index 8d13119f0..704167975 100644
--- a/anki/deck.py
+++ b/anki/deck.py
@@ -1616,7 +1616,8 @@ insert into undoLog values (null, 'insert into %(t)s (rowid""" % {'t': table}
         return self.redoStack
 
     def setUndoBarrier(self):
-        self.undoStack.append(None)
+        if not self.undoStack or self.undoStack[-1] is not None:
+            self.undoStack.append(None)
 
     def setUndoStart(self, name, merge=False):
         if not self.undoEnabled: