Luckily this is a very simple tweak, and you don’t even have to reboot Firefox.
I’m not sure if all versions of Linux have the same annoyance, but at least Ubuntu does.
Make Backspace Key Work Correctly in Firefox on Linux
If there's one thing that drives me crazy about using multiple operating systems, it's the inconsistency in keyboard shortcuts... when you hit the backspace key in Firefox on Windows it normally goes back to the previous page, but it doesn't on Ubuntu Linux.
