Great add-on. However, there are some issues with it, that makes it very annoying for me. Not sure if it's related to other add-ons (such as Session Manager), but here they are:
- "Move tab to" menu is in a sub-menu (takes too much time and precise mouse accuracy)
- Does not accept local (non-internet) tabs. As a web designer, this really sucks.
- After switching group, all tabs are loaded. I don't want that.
- Tabs disappear sometimes (not a lot and not sure when)
- It forgets a lot in which tab group you were last time and you end up with a copy of all your tabs in a non-group tab. (Probably after restarting Firefox, not sure)
To the developer: I appreciate your efforts! I really do. The rating just reflects my "annoyment" and is no reflection to you or your efforts.

Terrible. Lost all my important tabs. Burn in hell

Messed up all my tabs only get cryptic symbols for my 140 tabs
example of tab url:

moz-extension://47d18f13-11b1-42af-a084-593b87913208/replaced/replaced.html?state=redirect&title=Newegg.com%20-%20Newegg%20shopping%20upgraded%20%E2%84%A2&url=https%3A//secure.newegg.com/NewMyAccount/AccountLogin.aspx%3Ftojump%3D0%26nextpage%3Dhttps%253a%252f%252fsecure.newegg.com%252fNewMyAccount%252fOrderHistory.aspx%253fRandomID%253d44983722522043620180414112356&favIconUrl=https%3A//c1.neweggimages.com/WebResource/Themes/2005/Nest/Newegg.ico

Tiene todo lo mejor de su predecesor además de funcionalidades nuevas y es muy rapido.

I love this extension; Groups are one of the most important features and you've implemented them beautifully. However, I have a question (and forgive me if this is the wrong place to ask, but I couldn't find anyplace else).

Are all my groups in memory all the time? Or only the active group? That's important for resource management.

Thanks!

This is the best that ever came after Firefox killed the integrated TabGroup feature. Just wondering if there could be the option to set a shortcut key for backuping your tab goups to a json file?

I appreciate this add-on but I won't use it anylonger because the current version gives it permission to "Access your data for all websites".

Just amazing. Simply amazing. It moves my "Personal" tabs automatically to group.
There are few small things that can help like sync and hiding (instead reloading when switch)(And this is coming in next FF version so it will be implemented in new version of addon)

Thank you for reviving this add-on!! Works GREAT, almost better than the old original. Just one request: I'm losing my tab groups after I shut down FF. I thought that did not happen before, but not sure. Would it be possible to add an autosave / auto backup / auto start option?

But above all: thank you guys for the excellent work in making Firefox great again.

Lost all my tabs with this add on, I hate the new Firefox and this add-on don't help me to stay .

I can live with the clunky UI, but not with data loss. After a short time it began to pop up nonsensical error messages ("Not one tab was not synchronized" or something). At some point it never finished loading, and all my saved tabs were lost. Avoid.

It's the closest thing to the original Tab Groups that I've yet seen.
Pluses: CLEAN and neat interface. Great Layout idea. Easy to shuffle things around by Drag and Drop.

Very awesome! Brings back one of my favorite features that was removed from Firefox.

All good but would like the ability to leave tabs loaded when switching groups. Would save a lot of logging in and out. As someone else said, if the memory gets out of hand, closing and re-opening is easy. Yes, that also means losing logins, but it's the difference b/t logging in and out of sites several times a day (current) and re-logging-in to sites after a week or more when it's time to restart. A lot of people wouldn't need it, but the option would be great.

Very promising Tab Groups successor.
Edit:
After 3 years this had become one of the most irreplaceable must-have extensions for me, and I have to commend the developer for still maintaining it. I'm still baffled why such useful functionality (Panorama) was removed from FF in the first place.

This is a great addon, but I'm sticking with an older version because the current version gives it permission to "Access your data for all websites".

I realize that this permission is being used to create site thumbnails, but would it be possible to create a version that doesn't include thumbnails so that such a broad level of access isn't required?

FINALLY A PLUGIN REALLY THAT WORKS!!! As a web developer, I have like a million tabs open at the same time and this feature is a MUST HAVE to allow me to group tabs! (I started grouping tabs before Firefox added the feature, so I move to firefox feature, then they removed it and I started using a plugin but It stopped working .. was missing this feature untill now)

This is a terrific, must-have add-on for researchers and people with busy, creative lives. As a researcher, graphic designer and IT professional, I am often involved in dozens of projects at once and it's not unusual to have dozens of tabs (often several dozens) for each project. This add-on allows me to segregate them into logical groups and call up and use just the group I need, organized the way I want.

In locating parts and ideas for building a custom PC for a client, for example, I may open and use dozens of tabs; with this add-on, I can keep them all grouped under the client's name and share them with the client.

I work with Adobe Illustrator a lot; with this add-on, I can organize the pages, tutorials, online graphic resources, etc., in logical groups, available at the click of an icon. These are just a couple of examples; I have over 25 such groups right now.

I was using Tab Groups by quicksaver (a thousand thanks to you, my friend!) and actually stopped upgrading Firefox at v54 so that I could keep using this essential (for me) functionality. Glad to finally find a worthy successor to that add-on so I can keep working the most efficient way for me! I can hardly recommend this add-on highly enough!

Really great to see this extension, but please please allow the user to select whether or not tabs are closed in the current group when switching to a new group. I would even suggest to make it the default to keep all tabs open when switching since the current system of closing tabs will cause more headache, confusion, and mistakes from your users than any benefit like a lower memory footprint would make up for. It takes 5 seconds to close and re-open FF if you're looking to free up resources.

Great working app. Works fine and provides the missing functionality after the recent switch of app functionality. Great that it also describes the reasons for the required permissions. Still would like to see that 'Access your data for all websites' requirement is removed, this permission just for favicons seems a bit overkill.

im totaly excited having this add-on. it just does what i need. stable, nice, easy to use. i followed the dev from the first day, it had had all of those bugs, growing to a "version" i trust in for my daily shit i want to do with it. thanks guys .. realy appreciate what you've done so far. thanks! happy to support were ever i can...
for the negative comment from jonnoN some days ago:
"Unloads tabs that are not in the active group. Want to listen to music? Too bad! Useless."
--> mate, just pin the tab you want to listen to and it stays active. ... don't rate it bad for that, please