works well, feels like using safari tab groups sidebar

Simple Tab Groups? I suppose it's simple to use but it's anything but simple in functionality! Wow. What can I say? Firefox actually works, unlike Safari and this extension actually works, unlike Safari's tab groups. This will change how I work and browse. Thanks!

It would be great if the developer could add "subgroup" functionality to the extension. I right now have 65 groups open lol. I would love to be able to put each groups into categories. For example., if I am doing research on topic X, Y, and Z, and have groups named X,Y, and Z (respectively), I would love to be able to put all three groups under one group called "research". Hope that makes sense. I'd hazard a guess that this shouldn't be too difficult to implement. Many thanks to the developer for this extension, it has made research so much easier.

A must-have for Firefox users!

wonderfull extension, a must have.
The only thing lacking would be to have a "pin inside a group" feature ... (yes there's already pin out of it)

Thanks a lot! That's what I was looking for after switching from Chrome Spaces. Wish the developer and addon a long life!