While we'll reporting things here, please remove the `delete` to go back, it has fucked me over so many times in text fields. No other browser does it.
https://bugzilla.mozilla.org/show_bug.cgi?id=1041377
That key binding was added for interface compatibility with Internet Explorer, which is less important these days. If you'd like to disable it now, go to about:config and set browser.backspace_action = 2.
http://kb.mozillazine.org/Browser.backspace_action
Apparently, you can use value 1 to use backspace to scroll a page if you like!