Hi, the full-screen-api preferences refer to the type of full screen that websites can call up -- for example, when you click the fullscreen button on a video player. So those are not relevant to your main issue.

The chrome folder needs to be placed inside your profile folder (alphabetically just above the crashes folder). You should be able to:

• right-click the chrome folder > Copy
• double-click into the first listed folder
• right-click a blank area > Paste

Then the next time you start Firefox it should find the userChrome.css file. (That assumes you also set toolkit.legacyUserProfileCustomizations.stylesheets to true in about:config.)

Thanks for the reply! But I did both of those things and it unfortunately did not fix the issue, does the code inside of the userChrome.css file need to be :-

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

1. fullscr-toggler { display:none!important; }

or

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

1. fullscr-toggler { display:none!important; }

?

This site interprets many characters as formatting codes, so it's messy to paste code here. In my opinion, you don't need a namespace line. It should work with just:

#fullscr-toggler { display: none !important; }
 

Is it possible you are running one of the other profiles at the moment? If you go to the Troubleshooting Information page and find the Profile Folder row in the first table, that should pinpoint it. It's under:

• menu button > Help > More Troubleshooting Information
• (menu bar or Alt+H) > Help > More Troubleshooting Information

Actually, the namespace line prevents it from working because, at least in Firefox 137, it is an HTML element and not a XUL element.

<html:div id="fullscr-toggler"></html:div>
 

So there's yer trouble. Probably.

Old comment: https://www.userchrome.org/adding-style-recipes-userchrome-css.html#namespaces

I went through some of the older reddit posts in r/FirefoxCSS and I figured out the issue, the @namespace statement was causing the issue. Once I removed that it works normally, although I'm still not sure how to remove the fullscreen animations for regular sites.

I didn't see your comment about the namespace line lmao, thanks for the help big mans.

If anyone else is looking for the exact problems that I had, paste in

#fullscr-toggler {display:none!important;}

#navigator-toolbox[fullscreenShouldAnimate] {
    transition: none !important;
}

into your userChrome.css file, the first bit of code makes it so the toolbar doesn't appear when you hover your cursor at the top of your full-screened window. The second bit of text completely disables the sliding animation of the toolbar when you hit F11.

You can clean up the code in your solution by starting with a <pre> tag and ending with a </pre> tag. Otherwise, copy/paste is broken.

Like this?

    fullscr-toggler {display:none!important;} 

    navigator-toolbox[fullscreenShouldAnimate] { 

   transition: none !important;

}

Thanks a lot for your help jscher2000 :3