You can still mod Firefox's UI pretty easily, its all defined by CSS files and not too difficult to customize. I for instance actually did the opposite of what

You can still mod Firefox's UI pretty easily, its all defined by CSS files and not too difficult to customize. I for instance actually did the opposite of what you wanted and completely got rid of the tab bar cause I use Sidebery for tab management: https://i.imgur.com/cHz1clI.png https://i.imgur.com/cHz1clI.png Theres a whole subreddit for it even: https://www.reddit.com/r/FirefoxCSS/ https://www.reddit.com/r/FirefoxCSS/ This repo (and that subreddit) has all the info on setting stuff up in Firefox: https://github.com/aris-t2/customcssforfx https://github.com/aris-t2/customcssforfx and even has a CSS example for doing multi-tab lines: https://github.com/Aris-t2/CustomCSSforFx/blob/master/current/css/tabs/tabs_multiple_lines.css https://github.com/Aris-t2/CustomCSSforFx/blob/master/curren...