It is the reason I switched to Firefox. Had to write some CSS, though.

hermosa

Tabs often move from their custom group to the default group. Makes grouping useless

Added five minutes ago and it's already blown my mind. I feel like I'm rediscovering Firefox. Excellent!

Excellent! Great addon, more useful than TreeStyleTab: It has all what you need out-of-the-box. Many preferences with logical structure. Great thanks for Snapshots - It safe me few times and I didn't waste a lot of time for recovering. I especially like a feature to save the whole tree of tabs as bookmark: add with fool folder structure or just as group of standalone tabs. It's beautiful and handsome, no doubts ♥

After rebooting computer - all settings gone