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I was having the same problem. It ended up being the jquery.dimensions.js plugin. If I removed it, everything worked fine. I included it because of another plugin that required it, however I found out from the link here that dimensions was included in the jQuery core quite a while ago (http://api.jquery.com/category/dimensions). You should be ok simply getting rid of the dimensions plugin.
Just solved the same problem, the issue was that i did not imported some js files, like widget.js :)