Tab Rename

Simple and efficient

One problem. When the address bar is has a white background, the pen symbol does not show at all, as I suppose the pen is white. You seem to have done your pen in the address bar only when the address bar has a black background. BUT you forgot to do it for when the address bar has a white background and, in such a case, the pen should show only if the pen is black in this second case; in my case, a full white space on my address bar. Moreover, it would be better to allow an icon of your addon to be pinned to the toolbar instead of using a full space on the address bar for every single tab. Especially considering the fact that your space on my address bar (that has a white background) shows only as a white space without displaying at all a black pen because you created only a white pen for your address bar that has a black background.