sounds like maybe she knows you will give her the attention she is vying for when she huff huff sniffs when you are in the room, and when you are not there it's not worth the effort because she is smart enough to know how to get your attention, and is quite well adjusted, as a matter of fact sounds like she is trying to manipulate you just as she "may do at home" to get attention as well. Def. don't think its a case of her not liking you....more a case of her trying to see what she can get from you. I would just ignore her huff huff sniffs and play with the other kids, until she realizes, "your not going to cave' and beg for her happiness. Good Luck!