Hey I read through the provided PDF manual and it says middle mouse (or LMB+RMB at the same time) will make an object "active". I'm assuming that means it'll equip it or 'use' it (potions, roots etc).
But for some reason, MMB in stonekeep seems to do nothing. LMB+RMB at the same time also does nothing. Well, all MMB does is it 'picks up' an item: It doesn't actually use it.
Am I misunderstanding something here? It'd be very nice if MMB would 'use' an item because clicking+dragging roots to heal up is a pain!

OK I think I figured it out. MMB is the same as picking up an item, but it doesn't open the inventory screen as well. It's useful if you want to walk around with the orb to look for secrets.