Been using Tree Style Tabs for years but found this and decided to give it a whirl. After three days, decided to clean up a mess of tabs. Selected one tab to keep, clicked "Close other tabs," and sure enough ALL other tabs closed. Unfortunately that included ALL my pinned tabs!! MAJOR oversight!!! Uninstalled. I'll stick with Tree Style Tabs. I find it far better designed and better thought out.

Edit for added detail: A few other reasons I've ditched this in favor of TST:

Messed up the order of pinned tabs
Doesn't have a decent way to organized tab groups automatically with good settings
Appearance settings are way to convoluted. Users shouldn't have to be web designers to understand what to do with appearance settings. There ought to be a few graphical examples of choices. Keep it simple stupid. Simplicity is always better.
Honestly, I find the appearance in terms of usability far to cluttered.

In short, IMHO, Tree Style Tabs is so far ahead of this extension in terms of feel, look and usability right out of the box this one just isn't worth the time. Yet...