Follow the instructions here Customize Firefox controls, buttons and toolbars.

EDIT: Actually, that doesn't mention how to resize. I am able to resize by dragging from between the address bar and the search bar.

Actually, it is not the toolbar itself I want to shorten, it is the location bar. It takes up so much space, you can't use personas that have any graphic on them, it just covers them up. Thanks for the help--if anyone can help with the location bar, I would appreciate it.

One thing you can do is customize your toolbar (see the article I posted above) and drag a few Space 's to the right of the location bar. It does the trick for me (though a little painful process).

The location bar and search bar have a flex property and take all available space.
You can change the relative size of both with that resizer between the two bars, but that won't change the space that both take.
You can add Space elements at the right of the bar in the "View > Toolbars > Customize" window to make the location bar shorter.

You can also set a max-width for both bars with code in userChrome.css below the default @namespace line.

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

The customization files userChrome.css (interface) and userContent.css (websites) are located in the chrome folder in the user profile folder.

• http://kb.mozillazine.org/Editing_configuration

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

#urlbar-container { max-width: 400px !important; }
#search-container { max-width: 200px !important; }

"Place the mouse cursor between the location bar and the search bar. The cursor should change to a resizer that you can drag left or right to change the width of the location bar and the search bar."

I found this at https://support.mozilla.org/en-US/questions/690807?s=address+bar+size&r=15&e=un&as=s Thank you very much, TXGuy.

Note: This only worked when I removed all the symbols that I already had in that space (Reload and Stop). I did this by dragging them to the Customize screen (View, Toolbars, Customize), resizing the location and search bars - very easy, and then dragging them back into place.