I installed:
“Classic Theme Restorer (Customize Australis) 1.2.2”
It has reset back most of what I had.
https://addons.mozilla.org/en-US/firefox/addon/classicthemerestorer/
I still have that red. It is now blended with grey.
It turns out it is your title bar color under Personalize in Windows 7 (control panel). Change that color and it changes in Firefox.
Why would Firefox even pick up that color?!!
After more searching I found a post that fixed the color issue for the toolbar menu.
Open a new tab and type in the web address field: about:config
Scroll thru listed to find: browser.tabs.drawInTitleBar
Change by double clicking to: false
Now back to the normal grey color!!