If I remember correctly, Firefox have global scaling factor for the entire browser, including toolbars and content.

Step 1: Open a new tab, type or paste "about:config" in the address bar and press Enter. Click the button accepting the risk.

Step 2: In the filter box, type or paste devp and pause while the list is filtered

Step 3: Double-click layout.css.devPixelsPerPx and change its value to 1.5 and click OK. That corresponds to 150% of the classic font size. Originally is -1.0 from my side. You can play around it between 1.0 to 4.0 in order to suit you.

Noted: Before doing this, please do remember your initial settings in case you want to change back.

I hope this will help you.

Hi Barry, there is a way to restore the Compact density. That's the easiest thing to try. See Compact mode workaround in Firefox or https://www.userchrome.org/firefox-89-styling-proton-ui.html#compactmode.

Otherwise, I have a rules builder which you can use to can re-connect the buttons as tabs and shorten their height.

• Code generator: https://www.userchrome.org/firefox-89-styling-proton-ui.html#tabstyler
• How to install: https://www.userchrome.org/how-create-userchrome-css.html

To make the height of the tab bar less then you can use this code in userChrome.css.

Add code to the userChrome.css file below the default @namespace line.

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

/* ROOT - VARS */
*|*:root {
 --tab-min-height:      25px !important; /* adjust */
 --tab-min-width:       60px !important; /* adjust */
}

/* TABS: height */
#tabbrowser-tabs,
#tabbrowser-tabs > #tabbrowser-arrowscrollbox,
.tabbrowser-tabs .tabbrowser-tab {
  min-height: var(--tab-min-height) !important;
  max-height: var(--tab-min-height) !important;
}

See also:

• /kb/forum-response-tabs-below-url-bar Forum Response - Tabs below the URL bar | Firefox Help

Thank you for all of the solutions. I tried everthing and everything worked. Sadly i cannot choose multiple solutions lol. Thanks again