[JosephLark]

Damn it, I was hoping this was going to alleviate my main worry with this new Firefox - the UI. It's so Microsoft Edge-ified.

I had more trouble finding this setting than I should have. Appears to be hamburger menu -> customize -> (bottom of page) density drop-down -> select compact. Still not sure if I like it. The tabs alone are still way too big for my liking.

Coupled with Ubuntu 17.10 and the Gnome that brings, the top of screen is going to be eaten up by way more UI than I would like. Is there any way to get Gnome to have a unified Ubuntu/application menubar like Unity?

[482794793792894]

You can shrink the tab height further with userChrome.css. [1]

Putting this into there should shrink it down a bit further:

  @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

  #TabsToolbar {
      height: 24px !important;
      --tab-min-height: 24px !important;
  }

Obviously, you can replace those 24px with even smaller values. it just starts to look silly at some point, because the icons get squished. There's probably a way to tell those icons to scale down differently, if you do want to go even smaller.

You can load the URL "chrome://browser/content/browser.xul" to get the browser UI displayed like a webpage, allowing you to easily use the devtools to inspect the different CSS identifiers, so that you can mess around a bit by yourself.

[1] http://kb.mozillazine.org/index.php?title=UserChrome.css

[TD-Linux]

There's work to use Gnome client-side decorations for the title bar here, which should help with screen real estate: https://bugzilla.mozilla.org/show_bug.cgi?id=1283299

It probably won't land in time for 57, but hopefully soon!

[rainbowmverse]

>> I had more trouble finding this setting than I should have. Appears to be hamburger menu -> customize -> (bottom of page) density drop-down -> select compact. Still not sure if I like it. The tabs alone are still way too big for my liking.

Assuming it's the same as every Firefox since they started copying Chrome, the alt key should bring up the old-fashioned (and much more usable) menu bar.

[khc]

I use "No Title Bar" gnome extension and "Tab center redux" plus userChrome.css to move the tab bar to the side. The top side is actually quite compact.