4 ms·Tree Style Tabs is also the #1 reason for me.by DiThi 10y agoTree Style Tabs is also the #1 reason for me.taivare 10y agoare Tree Style Tabs an extension or now built-in.detaro 10y agoextension: https://addons.mozilla.org/de/firefox/addon/tree-style-tabs https://addons.mozilla.org/de/firefox/addon/tree-style-tabs