@mzeinali Fwiw, i've been monitoring their progress for months, in my #FirefoxNightly. It's still extremely primitive, & barely functional. The tab groups are merely single-tier [ie, there is no nesting nor tree structure], & though they now can be collapsed in the horizontal tabs bar, once you switch to the #VerticalTabs bar the collapse function fails. They are still so far behind the sophistication of #TreeStyleTab & especially #Sidebery AOs that i fear they'll never catch up... meaning this long-missing native function/feature will never become viable for me.

Atm my hopes are slenderly vested in #ZenBrowser whose Dev @zenbrowser months ago promised that fully nested native tree tabs were on their development path [https://l.opnxng.com/r/zen_browser/comments/1eqqzlt/the_one_feature_that_will_win_me_over/lhv19c4/?context=3#lhv19c4]. Until then, in all my Foxes, it remains #Sidebery all the way.

@Ashedryden For years it was #TreeStyleTab, but for some years now it's been / remains #Sidebery.

Okay. As one of my attempts to make a viral post, let me make a poll:

Since you're probably on desktop, and using a browser to read this post, may I ask you: do you use vertical tabs or prefer horizontal ones?