Many times when I'm working on Flash games I'll find that a particular combination of keys held at the same time doesn't register, e.g. LEFT, DOWN and SPACEBAR.
I know from my days playing Doom this can be caused by the keyboard hardware, but surely technology has moved on since those spongy beige PS2 keyboards?
So my question: are these problems caused by Flash, by the hardware, by the operating system, or something else?