I like this add-on and find it useful, but unfortunately it seems to cause my tabs to crash when I'm browsing or refreshing a site for a long period of time. I've ruled out all my other add-ons as the cause of these crashes. I believe it also has a substantial impact on rendering performance. Unfortunately due to these issues, I have decided to uninstall this extension. I will be very happy to use it again if these issues are fixed or alleviated.