The invention relates to a method and an arrangement for cleaning the screening device of a screen. The touch-sensitive input device comprises a first layer, a second layer facing said first layer, said first and second layers defining a cavity accommodating a substance capable of flowing, and an actuator device arranged to vary the pressure of said substance in said cavity so as to provide haptic feedback to a user touching a surface of said touch-sensitive input device. The conductor rail has a contact region for detachable connection to the foil conductor. According to the method, a plurality of control planes of different elevations are set relative to a control plane of a zero elevation of a reference rotating ellipsoidal earth model. Yet another attachment is an underseat storage compartment, primarily accessible by an attendant from the back of the chair.