I can not believe that this is the replacement for the old Tab Groups??? I just tried to restore 139 tabs and lost everyone of them. If I had just seen the restore session tab before I tried to use this extension: I would have been fine. I am NOT at all - in no way at all - liking this new Firefox except that it is faster. Yes it most definately is but Most of the fun using Firefox was the addons and extensions. That - by the way - used to work pretty darn well. Now there are Other extensions or Might we Say - No Extensions!