FIXED: Unfortunately, the latest version (4.4.2.1, from 26 Feb 2020) contains 2 major bugs, which ruined the previously awesome add-on:

1) When I now click the STG icon in the Firefox (v73.0.1) toolbar, the add-on shows me a listing of the _tabs_ in the active group, rather than a listing of all the _groups_ that I have created.

2) The "Move tab to group" functionality (from right-click context menu) no longer works. It seems to do absolutely nothing now.

(Assuming that the above bugs will be fixed soon, I'll gladly recommend the add-on to all users!)

– – – –
EDIT (5 March 2020): Yes, the update to v4.4.2.5 indeed fixed the bugs mentioned above. Superb! Thank you Drive4ik. =) =) =)

Дополню сообщение gamover
Версия 4.4.2.4, последнее обновление 26.02.2019, новые обновления не находятся. Кнопка TabGroup все еще показывает по умолчанию не список групп, а список вкладок в группе. Раньше было наоборот

Works well and has saved me many hassles keeping track of things. My only complaint is how it reloads all pages on launch, slowing things down.

Otherwise, a wonderful tool. Thanks for all your work.

Last update changed it to show all the tabs in your current group rather than the groups, making it extremely tedious to switch between groups. The addon is much less useful now. Edit: Fixed

If you use a lot of tabs and like to keep your sessions organized around themes, this is an essential tool. Don't leave home without it!

Кнопка TabGroup стала показывать по умолчанию не список групп а список вкладок в группе. Это очень не удобно. Почему-то стали дублироваться все вкладки в группе при ее открытии. Раньше все работало отлично.

Стоит последняя версия: 4.4.2.4 (по крайней мере обновлений не находит), но проблема с отображением вкладок вместо групп присутствует все равно.

Кто нибудь знает как отвечать на комменты здесь? Какая-то кастрированная система комментирования.

新版本工具列圖示點擊竟然改成展開群組。
關閉分頁後其他分頁亂跳，切換群組不順暢，毫無長進。

upd: Now that I understood, how to use regular expressions with this extension, it's become really helpful. Thanks for your help.

Smooth Extension but the Pocket button does not work.

Really useful and helpful extension that generally works quite well. The two things on my wishlist for it would be (1) some way of having it be able to run without making Firefox restore all my tabs when I open it; (2) syncing my tab groups across different devices (my home + work computer).

Hi. Love this! Took me a while to replace tab groups but finally I found this! Great job. I'm loving the workflow improvements it brings and it's first class in reliability too. Thanks you for creating this for everyone crying about the loss of tab groups, this is actually better!

DEV: One thing i'm not certain about is if it's possible to include pinned tabs under tab groups i create, is this possible?

This addon saves my ass. An incredible addon.

Has minor issues, but it's great. Went essential in seconds. Thanks, keep up the good work!

trying to export all my groups from sync tab groups hangs up firefox
it seems like it tries to open all tab in all groups which is just crazy and brings down firefox to crawl which is duh it's like over 2 thousand tabs sync tab groups must work in other way because I never had problem importing that many groups and tabs

and my system is not weak Ryzen 7 3700X and 16GB of RAM with Firefox running on ssd