Not sure if this happens in Mac, but it doesn't happen in windows, therefore Linux section:
When I try to bind an action to a key that requires Shift first ( capitals and symbols ) then the config thinks I'm trying to bind Shift as the button, then it doesn't display the Shift button as a bind, so you just kinda sit there and go "eh?". Then when you go to play and U press shift, then everything U just bound it to goes off.

Editing the config file works just fine.

Ok, that's being fixed.