When I press alt gr + , or . (= keys with symbols < and >) , it returns my page back or forward. Its the same as alt gr + left arrow or right arrow, but it happens only in Codecademy course. Tested it in chrome and edge, both same.
Hope you understand, thanks a lot for help. 
Does your keyboard not have those characters? Do you have a numeric keypad?
Alt + 6 + 0 => <
Alt + 6 + 2 => >Just tried switching to english keyboard and it works quite well… Idk why I didnt think about it before. 
I use czech keyboard layout, so the shortcuts are bit different (instead of shift in english keyboard layout i have to use alt gr for the same symbol).
Still I would appreciate if the shortcut for returning page could be removed. 