jquery/jquery-ui — pull request #728 by zhizhangchen (2012-09-13 05:18:18+00:00)
Title: Draggable: Fix a bug when dragging into nested sortables there are dupli...

...cated placeholders

Fixing ticket: http://bugs.jqueryui.com/ticket/7777
Solution example: http://jsfiddle.net/zhizhangchen/GZ6Qr/