From version 90 or so, Firefox happily joined the stupid flattern IU design in an stupid cometition between developers of wich UI becomes more flat, more simple, more confusing, more autistic. A horrible UI wich has a rather mediocre way to personalize it with ugly skins and ugly interfaces to tweak little changes to make it more confusing. So the only way to tweak the UI in a way to make it more useful is to tweak some lines in a obscure CSS file hidden in the deepest abyss of firefox internals (wich you find after countless hours searching on the more and more obscure and scarce forums in the post instagram-tiktok-social-superficial-stupid SEO-driven internet era) until you find some personalized UI apearance that resembles something more usable and intuitive... But finally you need to upgrade firefox to prevent security breaches and... voila! all the personalized configuration flused away messing the UI in an unusable state, for example hiding the tabs, mixing them with menus, etc. No way to roll back that catastrophe. The only solution to try to revert that mess is to try to get into the wilderness of manually rollback to previows version, wich in any way guaranties get the things back again.
