From 73380ca442f77bc88cc875efe4b42ab2b3e66b72 Mon Sep 17 00:00:00 2001
From: Jonathan Frederic <jon.freder@gmail.com>
Date: Wed, 18 Dec 2013 14:46:25 -0800
Subject: [PATCH] Fixed nonregistered model bug in wiget manager

---
 IPython/html/static/notebook/js/widgetmanager.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/IPython/html/static/notebook/js/widgetmanager.js b/IPython/html/static/notebook/js/widgetmanager.js
index 4ad3b6e68..369ed620b 100644
--- a/IPython/html/static/notebook/js/widgetmanager.js
+++ b/IPython/html/static/notebook/js/widgetmanager.js
@@ -78,7 +78,7 @@
 
         WidgetManager.prototype.get_model = function (widget_id) {
             var model = this._model_instances[widget_id];
-            if (model.id == widget_id) {
+            if (model !== undefined && model.id == widget_id) {
                 return model;
             }
             return null;