HERE IS THE CORRECT ANSWER for Firefox version 9.00 of how to achieve it now edited into my very first question https://support.mozilla.org/en-US/questions/1339095

When I used your solution I have run into an issue.

As I create new tabs they extend to only half the browser window. As they are created, they only take up a limited amount across the top.

I've attached an image to provide an example.

How do I get this to extend to the full space of the browser window?

Thanks

I managed to get the tabs to extend across the full window. Now there's another problem.

How do I get the tabs bar to match the height of the tab specified?

I managed to get the tabs to extend across the full window. Now there's another problem. How do I get the tabs bar to match the height of the tab specified?

Hi Photoparity . . . it took me ages to get mine right (as you can see from the number of questions and replies in that thread). I had to keep altering the heights on mine, by altering this information below, (if that helps). It was originally suggested to me to use a smaller number, but when I did the menu was squeezed up and no address-bar showing, so I set mine to 45px

You can modify the 45px in this line below, if you wish to get an appropriate height . . just experiment with different numbers till you get it right --menubar-height: 45px; /*30px|41px=11px; caption buttons on menubar*/

Hi Photoparity, your buttons look extra-tall. Are you using "Touch" as your Density selection? I think most solutions are designed for Normal or Compact, so definitely some values will need to be tweaked with Touch density. If you want to experiment with a different density, it is set on the Customize tab (or you can use about:config).

• Customize Firefox controls, buttons and toolbars
• about:config values: https://www.userchrome.org/firefox-89-styling-proton-ui.html#compactmode