I've been looking for this for a long time.

Works somewhat well. Close to Edge sidebar as you can get with Firefox.

Fantastic extension, of which I use probably 20% of the feature set. Right click to close a tree is especially valuable, as is moving a tree to a bookmark folder.

Thank you to the developers!

Significantly better than Tree Style Tab.

This is what I've been looking for, the equivalent of Profiles on Safari. Where can I donate?

This is probably the greatest plugin I have ever used on ff. It completely changed how I use my browser, in a positive way, of course.
Great work !

This extension is the reason I use Firefox as my main browser rather than Chrome or Edge. It is got so many options and settings to customize to your needs that it is invaluable to the tab hoarder.

Useful to use in combination with Auto Tab Discard Extension to prevent many tabs slowing down your machine.

Very thoughtful add that makes my job much easier

Great extension for vertical tabs. Works flawlessly, no bugs and no crappy animations like other extensions I tested. Grouping tabs by right-clicking is super useful, it's like bookmarks but better. Speaking of bookmarks, you can select tabs and bookmark all of them at once, super useful. The sections, used with Firefox Containers, are super great to separate work, school, and personal things. Unloading tabs is also a functionality that I think is super useful when you want to keep tabs in the sidebar but don't have them loaded.