The new version 2.02 hanged completely my Gmail, without any possibility to do anything, due to the opened window telling that a bug was preventing a script to do its job, this window being NOT closable (no effect for any of the buttons) !!!
Yes, indeed, a very hard bug !!!
I had a very hard time trying to uninstall it, finally figuring out how to do it : firstly to close my Gmail tab, then uninstall wisestamp, then rebooting firefox