This isn't just a problem with the address bar, it also applies to HTML inputs and textareas. From my understanding it stems from how Firefox renders and synch

This isn't just a problem with the address bar, it also applies to HTML inputs and textareas. From my understanding it stems from how Firefox renders and synchronizes frames. I've filed a bug two months ago, but really unsure when it will get resolved. https://bugzilla.mozilla.org/show_bug.cgi?id=1408699 https://bugzilla.mozilla.org/show_bug.cgi?id=1408699