How do I split a stack of consumable items?

I've got a stack of potions. Five of them in fact. It sure would be nice if I could put one of them into each of my party members quick slots for use in this really hard boss fight I have coming up. The usual suspects for stack splitting - shift click, control click, alt click, click, then shift click to drop, don't seem to be working, so...

How in the hell do I split up my nice stack of potions before the big fight?


Double-click the stacked items, choose how many instances of the items you want to move, and click accept.