Sounds like she probably likes you and she afaid to admit it
Honestly, her behaviour sounds confused - which is very likely why you're confused. It does sound like she's trying to make you jealous, but as for -why- and to what purpose, I don't know.<br />
Seriously, you should talk to her. Make sure your questions are simple, pointed, and not an attack. Use 'I' instead of 'you'. Try to come across as the mature one here and don't let her put up easy defenses like "you're needy" or "it's not a big deal." I can't guarantee a straight answer or instant resolution, but if you dance around the issue, and she continues to act weird, things are just going to get worse.
Sounds like she is trying to make you jealous. The fact that she is doing it in front of you and then looking to get your reaction makes it seem that way to me.