BTW AA is enabled when you set the AA ingame in options without restarting
Activating AA in the options menu, or forcing it in the control panel, and actually getting AA, are two different things. At least in Divinity 2 that is! Atm you can set AA to whatever you like, 2x, 4x, 8x, whatever, the game will still not give you any AA.
I play in 1680x1050 and the missing AA is one of the greatest faults I currently see in the game.