Hitting a key with an ammobox open scrolls to the first item starting with that letter, it also makes you do whatever that key is bound to (not bad for stance changes, bad when you throw a grendade)

The ideal solution would be for non-inventory actions to be disabled when the inventory is open, and to expand this feature so that you can type multiple letters. Instead of "M" scrolling to Mine Detector, I woud like to be able to type "MX" to scroll to the MX rifles.