She's so used to everyone walking on eggs around her; maybe it's time someone sat down & had a frank talk with her:
"Look, I know you don't like (person, process, whatever pissed you off today) but if you want to be seriously considered for a leadership position you're going to have to make changes. By doing X, Y & addressing Z you could stop being a bridesmaid & be the bride, so to speak. Are you willing to do what it takes or are you going to continue to sit & watch others pass you by?"