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.

Great extension for managing a bunch of tabs!

One annoyance: Sometimes when I click on a tab, if I'm moving the mouse a little it'll put the tab in a new window. Can be a little annoying to move it back if it has a bunch of branches.

Otherwise, great stuff!

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.