Quickly fixed after a faulty patch.
Awesome extension.
Has made my tab hoarding problem much worse.
100% recommended

thanks to the people in the reviews for showing the workaround for the bug in the latest update.

Latest version is indeed broken, but if you follow the workaround provided by the author it does work. I had to reload the extension after updating permissions.

A new thing I noticed, which may be a new bug introduced is that when I create a new tab from a grouping the new tab doesn't associate properly. It always ends up at the top level at the end.

version 3.9.21 "contains fatal issue on the startup. There is a workaround: grant an optional permission "Read and modify bookmarks" for this addon via the addons manager UI. The next release will become working without the permission."(c)developer

it's a shame to developer to push such version to production and does not provide fix as soon as he noticed it.

UPD: bug has been fixed in a few days, so the rating was fixed too.

Version 3.9.21 is busted and won't load. Click on "See all versions" to download and install the previous version which is working fine.

I wish they could have rolled back this version sooner rather than let it stay broken for everyone. But I don't know the FF addon release process to say if there was a better way to handle it.

Suddenly stopped working. Mac Sonoma 14.2.1, FF 122.0 (64-bit)

This is a great extension, one that I've been using for years, but the last update has MAJOR problems. It stoppped working on Firefox ESR 115.7.0esr (64-bits), the workaround suggested by its creator didn't do anything. On Firefox 122.0 (64-bits), the extension was apparently ok, but then I used that workaround giving permissions to "Read and modify bookmarks" preemptively and all my bookmarks were gone. DO NOT USE THE WORKAROUND.

With update 3.9.21 it just doesn't work. It doesn't show any tab in the tree when I first lunched Firefox, and left clicking the icon on the toolbar does nothing. Sometimes I managed to open again the extension by disabling and enabling it again, but tabs still won't show. I rolled back to 3.9.20 and it works well again (if memory gives me problems, I'll roll back to 3.9.19). Still, I want to give you 5 stars since I know you will fix this and I love the extension, thank you for it!

Edit: I updated to 3.9.22 and it's fixed, thanks!

Since the last update (3.9.20/jan 2024), extension slowed down everything, transforming FF in a memory eating black hole.

Please debug ASAP.

Rolled back to 3.9.19 and everything seems to be fine!

Раньше было более-менее нормальное расширение, а с последним обновлением это просто невозможно стало использовать. Жрет память как не всебя. За 7-10 минут использования и перехода по 10-15 вкладкам из 150 сожрал 23 ГИГА ОПЕРАТИВКИ, причем все остальное (дополнения и открытые страницы) уложилось в 4 гигабайта оперативки.

J'ai utilisé l'extension durant 3 semaines et depuis 1 semaine, l'extension à des fuites de mémoire
Ayant l'habitude de jouer avec une page web en fond, cela à fait planter mon pc à plusieurs reprises avant de trouver la cause du problème. C'est inutilisable actuellement et je suis passé à une autre extension.

I estimate that TST, all by itself, nearly doubles Firefox's memory footprint. Sidebery freed up 5-10G of memory for me by comparison (yes, way too many tabs...). TST should *not* be a recommended extension. Latest update of TST leaks memory *very badly* and crashes, taking other Firefox extensions and other desktop programs down with it when the OS starts killing things to free up memory. Sidebery is *much* more responsive & performant with a very large number of tabs. This alone will remove a huge amount of friction in reducing the number of open tabs. No more waiting for TST to catch up. Switching to Sidebery was no problem: all nesting retained. Disable TST. Install Sidebery and verify ok. Remove TST. Done.

I have been using TST for about 2 years. It is great and works great for a vertical tab setup.