Motor vehicle door with flush glass, corresponding window assembly and motor vehicle

The door has a unit moving a sliding plane towards interior of a motor vehicle, with respect to a closing plane in which a movable panel (4) is found in a closed position. The panel acts on a sealing device (1) so as to move the sealing device from a sealing position to an inactive position when the panel moves between the closing plane and the sliding plane. An independent claim is also included for a motor vehicle including a door.