Stopped working @ FF20 Rated 3 out of 5 stars
Stopped working completely for me with Firefox 20. Lost UI access to all tab groups and session backups and everything.
Sad how this is entirely abandoned.
Seems dead :< Rated 5 out of 5 stars
The developer's page is down, and I am running into more and more incompabilities with bleeding edge Firefox versions :<
Rated 5 out of 5 stars
Fabulous plugin that I hope will get developed for years more.