Rated 4 out of 5 stars
Sounded like just what I needed, but didn't quite do the job... for me.
It does exactly what it claims, it just seems that I have an additional problem, which it is not aimed at...
The dreaded orange button disappeared, but the extra title bar that it was on remains; reading downward... "normal" title bar, similar bar that had the button (but no title), menu bar.
As before installing the addon, the only way to get rid of the button's title bar is to turn the menu bar off and then back on again (every time I open a new Firefox window).
OK, I know the add-on page says not to post bug reports here, but it gives no ideas on where to post them instead!