There's a rare incompatibility with Tree Style Tabs (->TST).
When saving a session in Simple Tab Groups (->STG), the tree structure of TST get lost completely and as a result the stucture is gone.
This happens on :
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0
OS Linux 6.1.0-7-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.20-2 (2023-04-08)
OS Theme
and is a quite new problem.
Unfortunately I have no real idea how to check, which of both AddOn's produce the "error"...
Does anybody have an idea?
BTW... the rating will be reset after solving the issue, because I know STG since a long time now and used it many times... sometimes in the past though it came to my attention, rhat there were some incompatibilities from time to time - that's why I post this message here and in TST.

This whole extension is a bit tricky to use as it is "rough around the edges" quite a bit in multiple regards and the menus look like crap. However, once you figure out how it actually works and how to use it, then it becomes very effective and pretty awesome.
In all honestly: The real issue of it is not the lack of functionality, but the bloat of extra functionality in the multiple setting-menus, right-click menus and so on, because most of those features are entirely useless to 99% users of this, but can confuse the hell out of new users.

life saver

Horrible. I created a new group and it closed all my existing tabs. Originally, I thought I did something wrong, but many other reviewers had the same experienc. An add-on shouldn't be doing surprises like that.

Utilise depuis plusieurs année sans soucis. Toutefois depuis v5.1 l'affichage du conflit avec "tab session manager" est très pénible (quelque fois deux fenêtres à fermer) un pop up aurait peut être suffit.

Excellent extension; essential for anyone that gets easily overwhelmed and/or likes to separate their tabs by topic or workflow.

I tried numerous suggestions but could not even get this to work so uninstalling

Great for organization, but not fully compatible with multi-account containers and sometimes is glichy.

Not the type of groups feature that chrome has, still leaves the tab bar messy and crowded.

I thought I could use it to organize hundreds of opened tabs. Not only did it it fail to do that, it also irrevertebly closed all tabs when I was trying something out. That sucks hard!

Allows to organize hundreds of tabs.

As far as I can see, this is just a glorified bookmarks tool (which we already have). Why bother to install an add on for something we already have? I hope someone designs a tab groups tool like the one in Chrome.

I've installed the add-on just yesterday and already enjoy having a tab group per project instead of an unsorted pile of tabs. It works really good so far.

Just one problem I had: when I created the first group and switched into it, I was unable to find a way to go back to the ungrouped tabs. Is there even any? I think there should be an explanation in the readme.

I'm glad there was a simple solution: the app offered to move the tabs into the current or a new group, so I just put the ungrouped ones in a group called "Default" for now.

Simply The Best tab management feature

At start firefox this addon often not started correctly. I need manualy disable and enable it for work.
But if not see on this bug - addon is very nice.