Or it is being over ridden or the code needed needs to be changed. You will have to determine that yourself as it is now a custom and we ask that you remove your usserChrome file to see if it is working correctly.

So It works correctly by the image. USSER CHROME URL'S

• https://www.howtogeek.com/334716/how-to-customize-firefoxs-user-interface-with-userchrome.css/
• http://techdows.com/2017/09/classic-theme-restorer-userchrome-css-modify-firefox-57-photon-ui.html
• https://github.com/Aris-t2/CustomCSSforFx/issues/1
• https://www.accessfirefox.org/Theme-Font-Size-Changer.php
• https://www.userchrome.org/
• https://www.accessfirefox.org/Firefox_Accessibility_Themes.php
• https://www.userchrome.org/what-is-userchrome-css.html
• http://kb.mozillazine.org/UserChrome.css
• https://github.com/axydavid/FirefoxUI/blob/master/README.md
• https://github.com/wilfredwee/photon-australis
• https://www.reddit.com/r/FirefoxCSS/

Note not all code in one place.

Please let us know if this solved your issue or if need further assistance.

Thanks for your reply, and the cornucopia of links above. However, they are not related to my inquiry.

My code was not overridden, because my userChrome.css file has not changed since version 58. Nothing else was added, changed, or removed either.

It was only the update to version 59 that changed the size of the button.

And now the code I posted above is apparently being ignored by FF.

I would appreciate some sample CSS code that could be used to change the size of the tab close button, or at least confirmation that the code I'm using above to achieve this is correct.

Please do this to find out : SAFE MODE

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Advanced > General)
• plugins are not affected
• preferences are not affected

TEST

Thanks for your reply.

I ran FF 59 in Safe Mode.

What should I look for?

The tab close buttons are still the same size as in Normal mode (the X is too large).

See attached image.

The close X only consists of a SVG image, so you probably only need to remove the "*" to make your current CSS rule work. Note that bold won't work, you would have to create your own image.

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

• http://kb.mozillazine.org/userChrome.css

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

.tab-close-button {
 width: 14px !important;
 height: 14px !important;
}

Thank you, cor-el. That did indeed work!

Any idea why it worked with the "*" in the previous version, but not the latest one?

Regards.

You're welcome.

In Firefox 58 and older this was a toolbar button with an image.