Chakkman... just read first post in this topic, MI clearly explained.
It's about script in AHK who allows you to press another space, while one is already pressed, and still work! Normaly it blocks you, because just think, you can't press your space while it's already pressed, same in keychanger, remapkey, but it was special script to allow it. You don't need too good timing with it, because you don't care if you leave space or not, it works everytime you press it.