Great add-on. Thanks for your time.

This Add-on has really changed my workflow. I've been able to keep the things tiddy, Work, Projects, Entertainment. It's kept distractions at bay.

Developer also listens to us!!! hence the comment below from my old review.

Former Review 2 Stars: This has the potential of being a 5 star plugin but everytime I open firefox tabs are duplicated or triplicated.

I just installed it yesterday and so far it f*ck*d everything up it could.

1. I moved some tabs into a new window to convert it into a tab-group but I didn't find any option that offered specifically that. So I choose "Create new group" in the hopes it would do that OR open a new window where I could move said tabs afterwards. It emptied out the current window without asking for confirmation or even a warning instead. :-(

2. Needed to restart my PC so I "closed all [Firefox] windows on this screen" (or however this option is called in English Windows). I expected Firefox to restore both windows after I started it again. Instead it just opened the new little group from 1. and an empty group. My (ungrouped?) window with ~200 tabs was nowhere to be found. :-(

Luckily it seems I was able to restore most tabs that had vanished in both cases.

Very powerful add-on! There are a lot of settings!
But I can't change the parent folder for backup subfolder! How can I do it? It's very uncomfortable!

Seemed nice, but when I've first time changed to a group of a few selected from many tabs it hid them without an easy way to change back to the ungrouped ones.
I've found them under the "v" tab menu and saw an option to change them into a group, which I used, as I saw no other way to get back to tabs without groups. After a few minutes of CPU abuse the "Ungrouped" group had zero tabs. 400 tabs went straight to /dev/null.
So yes, a good way to clean out your stale tabs, short of removing your profile.

Edit: Now I'm torn, as I've found out how the "Manage groups" looks and works.

Nunca escribo reseñas. pero esta extension me dio justo lo que necesitaba, habian eliminado de firefox el agrupar pestañas en grupos. y esta extension me permitio poder hacerlo nuevamente. Muchisimas gracias.

The Very Best of the Best! Perfectly working, simple, fun to use, highly configurable, actively being developed from a very polite and professionally responding to concerns developer! HIGHLY RECOMMENDED!

the best extension ever

It's almost perfect. One thing is missing: an optional ability to remove empty tab groups (with unmodified title) automatically. I guess, this would be a quite easy feature and could help a lot.