Am 01.04.2017 um 10:35 schrieb fred.h...@gmail.com:
I was afraid to click 'inspect element' for two weeks because I did
not know how to remove it.
You can remove it any time by pressing F12. However, I agree it's a very
silly bug that needs to be fixed. I've created
https://bugzilla.mozilla.org/show_bug.cgi?id=1353152