Great, must-have addon, and first reason to using FF for me.
- Tst toggle hotkey change option is needed. f1 by default, srsly?
- Tab context menu needs custiomization too:
-- missed some important options from tabs (Send to other device, etc);
-- ... but its overloaded with items that I would like to disable

Also some occasional errors: seens descend background tab sometimes opens in wrong tree; multiple tabs closing sometimes breaks on halfway