jquery/jquery-ui — pull request #1213 by jbryson3 (2014-03-12 18:42:55+00:00)
Title: Add two guards against trying to remove null objects

I ran into a problem when doing a $.sortable('cancel') within a beforeDrop hook. The cancel was removing the placeholder, and then when the mouseUp event fired, it would execute similar code. Since there wasn't guards protecting against removing something from a null object, I have added them.