Ticket #2771: index.diff

core.js

@@ -146 +146 @@
 
         // Locate the position of the desired element
         this.each(function(i){
-            if ( this == elem )
+            // use === because on IE, window == document
+            if( elem.jquery ? elem.index(this) != -1 : this === elem ){
                 ret = i;
+                return false;
+            }
         });
 
         return ret;