adding 'use' functionality to inventory window

[random_guy]

I'm using a Sierra-style interface for my game, pretty much the default. But I want to add a function to the inventory that lets players manipulate things within the inventory window as well as selecting the inventory items.

I've tried working it out myself, but it's beyond me. I have searched the manual and tutorials and whatnot for how to do this, but can't find anything, possibly because I don't know the right terms to search for. Can someone walk me through what to do?

[Ashen]

BFAQ: Interacting with Inventory, and this fairly recent (less than a month old, post from xStaH on Being able to actually interact with items in GUI.

Same basic idea, the forum post just has more detail.