One Update: please allow the location of the the backups folder to be moved. I download to my desktop, and suddenly had a mysterious folder appear and didn't understand why. Still a fantastic program.
I've so badly missed Tab Groups, and this app is nearly a direct replacement. It functions well, is easy to manage. I love it. My one suggestion would be, remember what tab was last used in each group, so that when in "Manage Groups" it returns to that tab, rather than the first open tab in that group.

Thank you!!!!

I'm sorry to down-vote this add-on but it's just too unstable: as others have said, it can't separate the tab groups - they end up dumped in one group all too often, or I get a tab error message and they simply refuse to load. This happens in 2 out of every 3 browser restarts. It's too much.

It does the work properly. It's fast, clean, beautiful. Exactly what I need. Thank you so much.

I love it but:
1. If firefox is not closed properly it's really really slow to reopen it and restore the tabs.
2. There is an error "Invalid tab ID"

Great Add-on. Thank you very much.

It's so much more that i was searching for, a lot of thanks!

A nice addon to replace original Tab Groups.
But there are two majors problems :
1. At startup, Simple Tab Groups always reopen 2 or 3 tabs that where closed in previous session
2. It's no more possible to switch groups of tab after a few minutes of usage. There is an error "Invalid tab ID". Only possible way is to restart firefox or reload STG addon.
Note : I have near 300 tabs opened in 11 groups (75 in groups with most tabs), if this help

Update 13.02.2019
It look like version 3.3.7 fixed problems described above.
I have no more closed tabs auto re-opening and since update I don't have Invalid Tab ID error.
Or maybe it's Firefox 65 ? Anyway, 5 stars now !

It would be great if STG worked fine with the last Extended Support Release of Firefox (currently 60.3.0). This E.S.R. is used in corporate environments (like my government).

Unfortunately last STG available for this Firefox version crashes very often, mixes tabs between groups and ends up not showing the Group Administration Tab.

it just works.
it help managing multiple tabs and doing it pretty neat

Thanks for great addon.
I have question,
is there any way to change backup folder?

thanks for the fix ! it's good again

Your add-on is the main reason I decided to update my Firefox lately. But it would be perfect if the old "Move to group" feature in each tab's context menu is implemented, just like the good old days...

Quick little nitpick: opening a tab group tries to load every single tab simultaneously which for larger groups can lead to heaps of lag and ram usage. older tab groups only held onto the tab page and a thumbnail and loaded them when they were selected which was much better for me. Also the tab management page could be smoother. Lastly, I like how current pages can be retrieved when opening a tab group without saving to one before hand so I don't lose pages I didn't want to but I would like active windows to be saved to a new tab group automatically when switching to another group and not already a part of one but not with only "new tab" active.