Asassin's Creed

So i just bought this really great game, and i must say its really great.

But one thing that i cant understand (and im not sure if its a bug or intended), but when i lock on an enemy, the four buttons (attack, grab, step etc) grey out and i cant use them, to attack, i need to lock off the target. Im still early in the game, i just went out of the city you start in (where you fist get to ride the horse).

And also, what does Multi-Sampling do exactly, is it AA?

Thanks .

Btw, when i lock on, i get some tutorial message on how to perform a strong attack but considering how the attack button wont function when im locked on, i have a feeling i messed up the tutorial or something.

Ah i fixed it, turns out i turned on the setting that pressing the button to go to high profile (by tapping it), makes high profile stay there, and to go out, i need to press the button again (as opposed to default where you have to hold it).

Dumb me .