* * * Simply Perfect * * * - BUT why NOT USABLE for the newest Firefox version? Why not standard Firefox functionality anyway?
I can only cite former posts as:
"Dear god -- update this addon for Firefox Quantum! I don't understand how this isn't just built in functionality at this point, it drives me nuts. This addon works exactly the way it needs to and is perfectly functional."
Unfornately, for the newest Firefox version, there is no adequate other solution (I know of). It's just not the same, if the keyboard's CTRL button is needed. Remind yourself that e.g. Apple's business model is generally based on such simples things as simple removement of one button only, and very successful with that...