“90210” star Shenae Grimes, who’s in town interning for Teen Vogue, was shocked when she was asked about Trevor Donovan leaving the show at the opening of Beekman Beer Garden Beach Club. Asked how she felt about it, “Her face dropped. It was clear she was not aware of the news. She started making calls on the red carpet, holding back tears. She was heard saying on the phone that it was ‘unprofessional for cast members not to be formally notified when a change of this magnitude occurs,’ ” a spy said. Also there: Lance Bass, Kelly Bensimon and Nicky Hilton.