I seem to have found a bug in jQuery UI that duplicates dragged elements when one of the target sortables is hidden. I managed to duplicate it in a very simple jsfiddle. I am in a time crunch so I can’t really wait for a patch.
Here is the JSfiddle: http://jsfiddle.net/BpfGC/1/
To duplicate the bug drag a letter form the green box up to the red box then toggle the contents of the blue box. you will see a duplicate of whichever letter you dragged up to red. This is in Firefox and Chrome.
Can anyone figure out a workaround or why this is happening?
I think it is a bug when using helper: “clone” with a hidden sortable. I answered my own question above and when you hide the container it works fine. That seems like a bug to me.
so:
<ul class="sortable" style="display:none;"></ul>will reproduce the bug but
<div style="display:none;"><ul class="sortable"></ul></div>works as expected.