So, kudos to you for doing this, and I'm not sure how exactly it was implemented, but it looks pretty swell. Tree-style tabs is the main reason I refuse to update Firefox & use Waterfox/Cyberfox etc, and probably never will change this unless there is something of equivalent quality. This addon *almost* does it. Unfortunately, there is no hierarchy tree-style of tab organization, so it isn't exactly as useful as it should be. I would really love to see the ability to control the height of tabs.
Really love that this has a tab search! omg
Keep up the great work! :) Hope to see some changes.