This thread had me giggling.

Once I was at my ex boyfriends house, and we were having a nap, or he was. I remember him turning towards me, asleep, but his eyes were wide open and rolling. He was sleeping with his eyes open, it freaked me right out.

But yes, what your daughter is doing is normal. It sounds like she is sleep walking, but not actually walking. I used to sleep walk when I was a child.