I've just got my cp together enough to do some testing and I have come across a problem.
I've been changing button configurations on my cp via the tab menu in Mame to match the actual button layout in the arcade.
Well when I reconfigure the Ctrl, Alt, or Shift Keys via the actual cp button mame imputs both Left and Right of those keys. I have to actually use my keyboard and imput the Left Ctrl, ect.
Anyone else had this problem?