Sorry, The application works slowly, especially when switching between tabs and Panorama Tab Groups. This poor performance is since the fresh installation of this extension. It should be definitely improved.
I use FF Quantum 65.0.1 (64-bit) Portable version.

I'm sorry to down-vote this add-on but it's just too unstable: as others have said, it can't separate the tab groups - they end up dumped in one group all too often, or I get a tab error message and they simply refuse to load. This happens in 2 out of every 3 browser restarts. It's too much.

I love it but:
1. If firefox is not closed properly it's really really slow to reopen it and restore the tabs.
2. There is an error "Invalid tab ID"

效率低不说了，还丢组，上次重启Firefox之后就丢失了全部分组和标签。

With Firefox updated to v62 and addon to v3.1.1 it doesn't works. Tabs from one groups are shifted to others when change, and according to extensions like Copy All Tabs or All Tabs Helper, discarded tabs remanin loaded, showing rigth now more than 100, despite the current group has only 3.

Good first pass at this extension. Buggy - frequently, it will freeze up while switching tabs due to duplicate url's in more than one tab group.

I like most everything about this EXCEPT for the fact that the tabs reload whenever switching groups. That's very annoying. For example, if I download something in one tab, wait for it to complete, switch to a different tab group, and then switch back, the tab reloads and the file start to download again. That's just one example of the annoying behavior.

If it wasn't for that, I would be satisfied and would stop looking for a better tab manager. As it is, the search continues.

UPDATE: A later version of this fixed the tab reload issue, so now I'm much happier with it.

Changing groups just closes all your active tabs and opens the others. So when you switch back, all your tabs reload and you lose history (as in the back or forward button). Pretty pointless. It's about as useful as having a text file with links of your tabs, because you lose your history. This add on should take advantage of the new tabhide in the about:config and maybe that will help it work properly.
Also, even though I restore info from the old tab groups, it didnt bring the history so again i cannot hit back button. shame.

Fast switching still broken. Loading 74 tabs, taking ages. I don't want the tabs loaded even the active one, I can choose which tabs to load. Please fix. or provide proper instructions! Also are they loading from cache? They shouldn't be taking that long!
It just lost 40 out of 46 tabs, and pinned tabs, in 1 group after restarting firefox The list says there are 46 tabs, but only 4 in the drop-down list and the window.- why?.
It just lost tree tab structure, folders, groups and pinned tabs when I closed and re-opened a group. Incompatible with tree tabs - sometimes doesnt preserve Tree Tabs tree structure, never preserves folders or Groups, please fix or make that clear on the download page before people start spending hours setting up.
(It DID preserve tab renaming which is good)

When it works it is very good but these issues are becoming too much! Are you going to fix these and if so WHEN, please?

It seems to randomly create new groups and doesn't save tabs in your current group so that when you change groups and return to your original group lots of tabs have disappeared

使用两个分辨率不同的屏幕时标签组编辑页面有BUG；不能缓存网页，切换标签组必须重新刷新网页；使用之后便捷程度上没有明显提升。

分组会丢失掉, 不管是稳定版还是开发板, 重启下浏览器, 分组就没了

Reliability ZERO.
App full of neat and usefull functions. Works fast.

But evry day something happens that kills my groups.

for ex: If you close the window with alle the groups in it and restore it afterwards, tha taps arent in the group anymore. if you change to the saved group its full of empty tabs. some of the tabs might still work but most of them are empty.
all the groups are worthless because they are destroyed, without backup either way from firefox recovery session exprted tab backup you're screwed.
After closing and recovering the window you need to delete all the corrupted groups and save the currents window into a new group. you cant create tabs that arent in a group after you have already more than 1 group active.

Once All my groups just disappeared without warning. wtf?
and so on. full of bugs makes it unrealiable. but its potential is great.

This add-on creates the duplicate group each time I start Firefox. Idea of add-on is good, but this error makes it not convenient.

Not a big fan of this. I live and die by my tab groups, so when Firefox did away with them, I needed a replacement, so I downloaded this. After using it for about a week, I dont like it and am looking for a replacement. Why? There are numerous problems with it. Where do I start?
It forgets what pages you had loaded in some tabs
It duplicates not just tabs, but entire groups of tabs
If in tab manager, you delete one tab, it takes you to the top of that group of tabs immediately

But the biggest problem I have with it is this: every time you open the browser or switch between tab groups, it insists on loading every single tab in that groups. Did I mention when I first opened my browser with this installed it put all my tabs from all groups into one group? Yeah, it does that. So I had about 160 tabs and it insisted on loading every one of those pages all at the same time. I've been working to cut back and separate tabs into groups, but I still have maybe 75 tabs in the largest group, and I don't see any improvement in performance. I recommend downloading it because Firefox has screwed us over and this is the only game in town as far as a solution. But before you install it, I recommend minimizing the number of tabs as much as possible.

Reloading tabs is extremely painful when you have groups of 50+ tabs... This is the main issue with any tab group add-on that needs to be addressed I think. If opening a group means loading all tabs then this isn't a good option for my needs and I assume a great number of people.

It's better than nothing, but still a far cry from the original Tab Groups. To prevent repetition, I would like to refer to the comment of J-Dude and hope you will indeed improve this extension, so that it will really be worth using it.
It's a start, but you will need to keep up the good work to increase your number of stars.

Сегодня тестил это расширение. Переключился на новую группу, переключился обратно - а оно заново грузит все 100 вкладок. Я закрыл, подумав, что всё загрузится по клику в отдельности, но получил пустые страницы. Хорошо ещё, что все они сохранились в истории, но увы, вперемешку.
Тут увидел, что в расширении можно импортировать настройки из старого Tab Groups. Но я не могу найти файл настроек в поиске. Как это сделать? Хорошо бы инструкцию для импорта.

I look forward to when this can handle my everyday use as tab groups did. Right now it does not do what I need. I cannot easily move tabs between groups, cannot name my groups, and when I select another group I have to wait for all the tabs to reload which really slows things down. Also, if I have music going in a tab and I switch groups, the music stops. So right now it's a no-go for me, but I'm hopeful for the future of this Add-on cause I'm really missing tab groups since the Firefox Update.

I created a new group with a blank tab switched to it and when tried to switch back to the original group with all the tabs they were all gone. I'm using firefox 58 beta x64 on windows 7 x64. It would be nice if you open a github page to be able to leave you feedback/bug reports there.