My favorite extension. Works great with Firefox 57+. It has many options and also allows customization via CSS (I use it to increase font). It doesn't hide top tab bar because of API limitation but for me it is feature not bug :) because I sometimes use also top bar for example when I need more horizontal space.

The reason why I continue using Firefox. Viewing pages in a tree is a great way to keep track of my day-to-day projects.

Such a lovely way to view tabs!

Great way to organize tabs if you're a million-tab user like me.
One request (and I know it's early) - in Firefox Quantum, the tab bar at the top stays! So now I have 2 sets of tabs - the normal Firefox tabs, and the tree style tabs. Would be great if there was a way to hide the tabs at the top. Thanks!

This is the best extension ever. I would also like to be able to hide the tabs at the top in Firefox 57.0.

Can't imagine browser without this addon.
The main reason why I'm still on FF.

Great extension, but in Firefox 57.0, the tabs are still shown at the top of the browser, taking up space – I hope this gets fixed soon!

This is probably the main reason why I use Firefox!

This is the mother of all "killer apps" for all browsers. I've used tree-style tabs for years now, a great surprise that it was updated as a webextension. Firefox Quantum + tree-style tabs feels like the future. Bravo Piro!

That extension is one of the reasons why Firefox is so awesome! Thanks a lot for updating it to work with Firefox 57!

Hopefully the issue with an API for hiding the native tab bar will be resolved soon.

This is the most useful addon in the history of Firefox. As long as this addon is alive, I can't leave Firefox.

Very good extension, highly customizable.
If you want to hide the legacy tabs toolbar AND the title toolbar too, here are my settings :

* Disable title toolbar

* Tree Style Tab vertigo theme

* In your profile/chrome/userChrome.css file (create it if needed) :

#TabsToolbar, #sidebar-header {
visibility: collapse !important;
}
#TabsToolbar {
margin-bottom: -23px !important;
}
toolbar {
padding-right: 110px !important;
padding-bottom: 2px !important;
padding-top: 2px !important;
}
#navigator-toolbox::after {
border-bottom: 1px solid #474749 !important;
}

I like thin and clean tabs so I added these rules to the Tree Style Tab extra style rules :

* Custom Tree Style Tabs css :

.tab {
height: 25px !important;
border-top: none !important;
border-bottom: dotted 1px #ccc !important;
}

.tab .label {
font-size: 11px !important;
}

And voila, a single bar clean Firefox (tested on developer edition v58).

Just one feature request : a dark (not black) theme using the same grays than Firefox would be great !

Oh thank god the developer got this to work with the WebExtensions version of Firefox. I've been dreading the thought of losing this extension for about a year or so now, as I rely heavily on it for productivity. I don't really know what I would do without it - I guess I could have adjusted to Vivaldi's vastly inferior side tab system instead. But now there is no need!

Also, to get rid of top tabs as well, use this workaround: https://www.reddit.com/r/firefox/comments/721ieq/ff57_removehide_tab_bar/

And then go into Customize settings, and at the bottom check 'Tab Bar' to get back the top corner options.