User Agent: Mozilla/5.0 (Windows NT 6.1; rv:7.0a2) Gecko/20110805 Firefox/7.0a2 Build ID: 20110805042003 Steps to reproduce: 1. Start the study (install the add-on) 2. Continue using browser [Aurora 7.0a2] Actual results: There was a major performance reduction, most noticeable when switching tabs. It would become non-responsive at times, and in general a bad multi-tab browsing experience. Disabling the addon fixed it. Expected results: The performance hit shouldn't be noticeable (at least not like it did).