She sounds immature and insecure (boy have I worked with too many of those types). The schedule change thing is her way of "peeing" on "her" territory. Not to worry though. If she has been removed from certain assignments and others with less experience have been given more choice assignments, it sounds like her superiors are wise to her antics. This is indicative of a healthy work environment. If she gets cronies, or higher ups start defending her actions, then worry.
Just be professional at all times with her. Assert the way you do things, be consistent and swift with correction, and don't let her get to you. She will eventually provide everyone enough ammunition to fire her.