Yup, this is still allowed. See Customize Firefox controls, buttons and toolbars for more information on customizing the Firefox toolbars.

What icons is this about?

Are you talking about icons on the Bookmarks Toolbar?

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

• http://kb.mozillazine.org/userChrome.css
• https://www.userchrome.org/how-create-userchrome-css.html
• https://www.userchrome.org/what-is-userchrome-css.html

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

#personal-bookmarks .bookmark-item:not([container]) .toolbarbutton-icon {
 display:none!important;
}

Ok, I figured out how to create the new userChrome.css file in the right place. The file is now empty. Do I add the "default @namespace" line too, as well as the code that you listed below it? Thanks for your help

And yes, it is the bookmarks toolbar icons I am trying to remove, so I can fit more bookmarks

Yes, you can paste the full code posted above including the @namespace line. The :not([container]) selector means that you still have the folder icons with bookmarks folders. If you want to hide the icons for folders as well then leave out this selector.

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

#personal-bookmarks .bookmark-item .toolbarbutton-icon {
 display:none!important;
}

It worked. Thank you so much! I was using the Firefox 52.8.1esr channel since last summer, because that was the last update that didn't make you create the userChrome.css file.

In fact, for my main computer in my home office, I am still using that old channel. Am I at risk for exposure to some nefarious hackers?

Thanks again! Dave

And with your help, I am now on the Firefox 60.4.0esr channel on my laptop, with none of those pesky bookmark icons! LOL!

Firefox really needs to have this removal of the bookmark toolbar icon, a much easier process.

The last Firefox 52 ESR version is 52.9.0.

• https://download-installer.cdn.mozilla.net/pub/firefox/releases/52.9.0esr/

For many years, I used to use the "roomy toolbar" extension. And it worked great, until Firefox disabled it.

Oops. it was called the "roomy bookmark" extension