jQuery, ajax and click functions that don't work

So the issue today dealt with a page that uses jQuery to turn a selection box into a drop down multi select box. Check it out here it's a pretty nice plugin.
Anyway, I populate the page with my data, create the drop down and then when the drop down changes the page makes an Ajax request to reload the page with new data. The problem was that when the page reloaded the items in the drop down didn't work the same. each item consists of a label and a checkbox. The checkbox still worked fine the problem was that now if you clicked on the label it wouldn't select the checkbox. After some research I found there is a pretty common problem with Ajax and jQuery where the dynamically assigned functions stop working after an Ajax call. I set some break points in the javascript and verified that wasn't my problem, the functions to check the box when you click the label were still working. With some help from a co-worker we found that the plugin was creating a hidden div on the page and when I made the Ajax call that div was getting created a second, third fourth... time on the page. So a simple remove before making the Ajax call solved my problem and got the labels working again.