Others

Make sure to set browser caching correctly on the static resources. Right now, it's affecting the performance (and also scores in performance tests, clients loves scores). It should be an easy fix for you. As far as I can see, none of your static resources is using browser cache.

I use Safari so I didn't realise the popup was being blocked. I gave up thinking something was wrong with ConvertFox a week ago and just came back to it and finally worked out what was wrong. This would have made it a lot easier to identify the issue.