From 527db105550ebe903a3c4829b9efadc1588d1dee Mon Sep 17 00:00:00 2001
From: Doug Blank <doug.blank@gmail.com>
Date: Sun, 2 May 2010 13:46:23 +0000
Subject: [PATCH] Protect views with no histories

svn: r15300
---
 src/DisplayState.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/DisplayState.py b/src/DisplayState.py
index 58618657b..dcb03f234 100644
--- a/src/DisplayState.py
+++ b/src/DisplayState.py
@@ -421,7 +421,8 @@ class DisplayState(gen.utils.Callback):
         the given handle.
         """
         history = self.get_history(nav_type, nav_group)
-        history.push(handle)
+        if history:
+            history.push(handle)
 
     def set_sensitive(self, state):
         self.window.set_sensitive(state)