I use the accessibility feature called sticky keys in OS X, what it does is that if you press a command modifier key (Ctrl, Cmd, Alt, Shift, Fn), it stays "pressed" until you press another key. This is very useful if you often use your keyboard with one hand, and actually quite convenient even when you use two hands.
The thing is that if you press a modifier key twice it stays "pressed" until you press it again. While it is sometimes handy, for me it would be preferable if this aspect of the functionality could be disabled, since I trigger it accidentally every now and then.
I realize that if this is at all possible it probably means fiddling with some system file somewhere, that's fine. I just want to see if someone out there might know where to look? :)