Grouping of tabs has worked flawlessly for months, abiding by certain principles. Unfortunately, although I am giving it 5 starts for that reason, and because it is so central to the one thing in the firefox universe that makes it possible to take advantage of all that Knowledge by Organizing it (one of several essential elements / add-ons / extensions) it just broke. It no longer creates a clean hierarchical order with the new "empty" folder on top. The children that were arranged and grouped are scattered as peers above and below the new, frustrated, parent.
Looking at the developer site, Piro has been trying to give away ownership of TST More Tree Commands - I still think this one belongs in TST directly but okay - I get that. But things should be left in "good order." And I don't know what to do.

This extension is great, you do not use it very often but when you need, it saves you a lot of time. I really think that it should be with the main TST. Thanks for your work Piro!

I see TST as incomplete without this addon.

I was recently lamenting the loss of the "create new group from selection tabs" functionality from the main extension, so I'm happy to find it again here. (That's the only one of these feature I use, but I use it frequently.)

Useful functions, but frustrating to now have to have another extension installed just to create a group from selected tabs - that seems like core functionality of TST to me.

Thank you very much, having groups inside a tree tab manager is crucial ♥

How to indent or outdent via shortcuts?

"Create New Group from selected tabs" used to be a part of the main TST add-on, and is now provided here. I read Piro's comments about not wanting to maintain this add-on, and that makes sense to me, but "Create New Group from selected tabs" is pretty important so I hope that either that specific command gets moved back into the main add-on or someone else does pick this up to maintain it. Either way, all hail Piro!!

Also, the flatten tabs command in this new sub add-on should come in very handy.

revert this functionality to the main TST pleaseee

The addon works well - it does what it is supposed to.

I often use 'Create New Group from selected tabs', and this works perfectly.

Flattening tree works excellently