Thanks for the advice. Since I'm mostly running linux, I guess there's no easy fix on your side. Perhaps it's possible to recover the web link of the hijacked tab though, which would already help quite a bit.
While I love using Firefox, one thing is sometimes really frustrating: the "we just need to restart" thing. Perhaps that makes sense if the browser is never closed/restarted on a system running for weeks, thus being vulnerable to some security issues...
