It is a little bit buggy. Sometimes tabs will open multiple times and make huge mess.

too intrusive. OneTab does not requires so many permissions.
https://addons.mozilla.org/en-US/firefox/addon/onetab/

My comments in Portuguese and English:

Justamente por ser "Simple" Tab Groups, é prático para usuários comuns que precisam de praticidade para organizar numerosas abas abertas. Você cria grupos e os identifica como achar melhor, e em seguida arrasta para dentro de cada grupo as abas abertas, de acordo com os assuntos.

Por outro lado, uma grande desvantagem desse complemento é que ele força você a ocultar as guias agrupadas.
No agrupamento de guias do Chrome, seu grupo aparece como uma única guia que pode ser facilmente expandida e recolhida quando você deseja mostrar/ocultar todas as guias pertencentes a este grupo.

Precisely because it is "Simple", it's practical for common users who needs practicality to organize numerous open tabs. You create groups and identify them how to find better, and then drag into each group the open tabs according to the subjects.

However, a major drawback of this addon is that it forces you to hide the tabs that are grouped. In Chrome's guide grouping, your group appears as a single guide that can be easily expanded and collected when you want to show/hide all guides belonging to this group.

It would be great except that it keeps all your tabs open between sessions even if you set firefox to open a fresh session. If not for this I would give five stars. As is it is unusable.

Sadly it quite often drops all of my tabs and I need to manually add them back in. As far as the design goes, it's quite nice. When it works, it's useful. It's not as intuitive as the group tabs in Chrome, but that's a problem I have with Mozilla, not this extension. However, not being able to change the location of backups is really grating on me.

Questionable decisions:
1. removing groups will close tabs (!?!)
2. once I opened a group, I could not find a way to return to the non-grouped tabs.
Also, you cannot have multiple groups opened in the same browser window.

It worked the first day, and it hid all the tabs I chose that day for a while, but then yesterday the extension broke and I couldn't open the extension's menu, the extension UI didn't show up when I right-clicked on a tab, and then all my hidden tabs just popped up again at one point. I kept getting some error message and I didn't know how to fix it, so I uninstalled the extension and reinstalled it to see if that would fix it, it didn't.

Useless to me, as you cannot have multiple tab groups open at the same time. I was just looking for a way to group my tabs together, but it hides all except for the active group. Just not what I was looking for I suppose.

I don't get it, this thing is very counterintutive to use. I send a few tabs in a new separate group and they still appear under Hidden Tabs. I remove them from the Hidden Tabs folder and they also disappear from their new group. I restore them, open the new group and everything else disappears and goes to Hidden Tabs. This is not what I want. I want to have my rogue tabs open and always accessible, AND groups of tabs I can launch at will. 2/5 is probably too much but I'll be lenient.

It may by my particular experience by trying to import my groups from Panarama Tab Ghroups, but this extension consumed so much memory that turned Firefox unresponsive. The drag & drop functionality is sub par compared to other extensions.

It keeps crashing? Firefox becomes unresponsive and completely locks up. I have to restart start Firefox, when I check, all my groups have disappeared. It keeps happening, so I've had to uninstall.

Looks cool. I have no idea what it's doing other than creating new windows & making me worry that it's just going to lose the tabs I'm trying to save.

This esxtentio is veryuseful and worka well, However it needs a tab explaining some functions to users be able to use it.

Even the best browsers and computers crash some time or another.

It is possible to bzck up or restore the tabs. The button links are there, but not a ward about how to fo it. How to chose where from or where to.

There is also what I suppose to bve a very useful autimatic STG backup, but I cannot guess which is which with 149 files in 7 directoris. We have to do it blindly, and probably destroying what we want to repair.

If I could use the extention functions in full, I would give it 5 stars.

Lost tabs after a moment, so useless. Otherwise is the best ergonomic Tab groups add-on I tried.

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.

When I try to open a new tab outside the group/container it just automatically gets pushed to the current open group(and linked container) I couldn't open anything in another group/container that's not the current one

Keeps bugging out. Can't use the same container for multiple tab groups. Settings are ambiguously named so I can't tell what they are supposed to do.

I don't know what happened, but from some moment extension started to hide my tabs - I couldn't find an option to disable this behavior, it is very annoying. I want all my tabs displayed in a row, not to open a list every time and search from there.

After some time this behavior is back, with v4.5.1 (FF 79)