This is the exact opposite of simple. Check Sidebery for the simple (and also faster) one.

Not simple. It's hard to understand what it's even doing, aside from _definitely_ not what I want or expect it to do. The worst extension I have _ever_ installed, and I've installed some pretty terrible extensions. It's less than worthless. At least if it were just worthless, it wouldn't be a big mess to clean up after I uninstall it.

very counter-intuitive to use : if i wanted to group my tabs i want them in the same browser not in a different browser window

Does not work like the grouping of tabs in Chrome. This is a very counter-intuitive add-on. Don't know why it hides tabs that are not in a group. If you remove tabs from a group it just closes the tabs. If you have a group open and open a new tab the tab is automatically added to that group. Nothing works as I would like to work.

Wanted something like Chrome's grouping function and this is NOT it. Has built-in containers that cannot be modified and is terrible to use. Managed to lose a complete session due to how badly it is designed.

I can't get it to work. I had very high hopes for this add-on, but it is NOT intuitive. If anyone out there who loves it wouldn't mind giving a brief tutorial, I sure would appreciate it. When I add a page to a group, it creates a bookmark; that's not what I want. I'm trying to reduce the number of bookmarks I have. When I close a tab it seems to delete if from the group. That's absolutely not helpful. If I'm just using the tool incorrectly, I'd like some direction.

I just wanted to use this plugin to organize parts of my >200 opened tabs. After creating a group, I wanted to open one tab from the group. All tabs in the group were opened in a new window, thus I closed the window because I just want one tab from the group. After I closed the window, no firefox instance was running anymore, the session restore didn't work and all my tabs were gone. It would be very nice, if this plugin shows a warning on exit, if there are ungrouped tabs opened.

Can't see anything with a dark reader on, can't even disable dark reader effectively to make things show. I really want to use this extension but it's impossible to see anything.

I must either be missing something or this plgin doesn't play nicely with ABP but I simply cannot get it to remember a group of tabs even after ticking restore session... @Drive4ik - ever thought about adding instructions?!

Took a little to figure out how to use it. I would suggest setting up the hot keys to switch between groups.

I think it works best combined with containers. You can use this with containers to insure you always open the right containers and you can auto group websites into groups/containers

Deleted all of my saved tabs after using for a few months. Restore previous session option is enabled and had not issues until everything was gone one day. No way to backup or restore that I could find.

I have about 760 tabs in my session. I worked for an hour and a half with this add-on to set up my groups, and when I reopened FireFox, it had erased all of my work. This add-on thrashed my tabs, then refused to show the management screen. I could see it blink on, then disappear. Sadly, this add-on doesn't work with large tab sets. Good thing I backed up.
[edit] Yes, session restore is enabled. Always has been. How else could you amass that many tabs?

The recent update causes an issue with new tabs - have to retype what I am trying to do twice in order for it to do what I want (do a goolge search, or go to the website)

Did not actually save any tabs, groups kept being empty... only regained my tabs by uninstalling.

I really wanted to love this addon but it's just too stressful to use. As so many others here have already posted, the addon's default behavior of deleting the tabs I've saved into a group is completely at odds with what the addon seems to have been designed to do: group your tabs for opening whenever you want. What's the point of spending the time to create several groups and set them up complete with containers and color-coding if the tabs are just going to disappear? Such a headache. Immediately removed, going back to OneTab.

Worst tab manager ever. Always crash and remove all my saved tabs.

Can't give this any better rating as the add-on is not intuitive at all. I thought that the purpose is to open several tabs, save those tabs into a group and then reopen them again later. Problem is that as soon as you close the individual tabs they disappear from the group. What good is this add-on if the groups don't keep their list of tabs to reopen them later? There needs to be a tutorial that explains how this is supposed to work.

Deletes all of your tabs on startup or orphans them at the bottom.