Overall great, but it becomes too laggy when many tabs are opened.

Tree Style Tab de Piro (piro_or)

I can't imagine using a browser effectively without this. The non-existence of such addon for Chrome is also the main reason I am not using Chrome.
This performs well, has all features I need, is stable... what more can one want from a plugin.

The only downside is it can't hide the default tab bar, but the author explained that it's because Firefox does not allow that.

As one of those people that always had dozens of tabs open, this has saved so much time and effort from searching for a specific tab. It makes things usable again.
I've tried other tree style tabs for other browsers and none of them are close to as fully functional and useful as this one.

this is such a useful and helpful add on for people who work with open tabs and need to manage them. Thank you!!

my god, this is exactly what i want...!!!!! thank you!!!!!

I love this.