Good gosh, what's the problem with the ALT key in Beyond Divinity? It's not like the "All Revealing TAB" from Neverwinter Nights - now that one was a big spoiler till Bioware put in hidden doors and triggers.
The ALT key in the game only show the 'normally' interactive items in the game, like dropped items, doors and chests and etc. It doesn't show off special triggers, like the talking skull, the cracks in the wall, the picture of the damned one etc. etc. etc. The developers indeed already develop a "hidden" flag for objects which they want us to find.