diff --git a/lib/web/extjs/defaults.js b/lib/web/extjs/defaults.js
index 5203e1a6fe27a..d4047c3ddf302 100644
--- a/lib/web/extjs/defaults.js
+++ b/lib/web/extjs/defaults.js
@@ -1,4 +1,13 @@
+/**
+ * Copyright © 2015 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+/* global Ext*/
 define(['extjs/ext-tree'], function () {
+    'use strict';
+
     Ext.UpdateManager.defaults.loadScripts = false;
     Ext.UpdateManager.defaults.disableCaching = true;
-});
\ No newline at end of file
+    Ext.BLANK_IMAGE_URL = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7';
+});