A window assembly for a vehicle includes a window panel (14), an actuating assembly (24) and a seal (22). The frame portion (16) partially surrounds a perimeter of the window panel and leaves a free perimeter portion (14c) of the window panel (14) at least partially free. The actuating assembly (24) is positioned at or near the free perimeter portion (14c) of the window panel (14) and is operated to vibrate the window panel. The seal (22) is disposed along the free perimeter portion to substantially seal the window panel relative to the vehicle panel while allowing movement of the window panel in response to the actuating assembly.