A few extensions, but I disabled all of them and had the same problem after reloading the page. That was with Firefox v. 59.0.2 (32bit).
I just found the solution myself (kinda by accident). toolbar -> tools (drop down) -> Options -> scroll down to 'Browsing' settings.
Had it ticked on to search for text when I started typing. for some reason the function didn't recognize keystokes as game input. (i've never had the problem on other games so never knew there was this option.)
Thanks for checking in though.
