A faceplate structure for a load control device comprises a bezel, an operating knob extending through an elongated rectangular opening of the bezel, and a sliding cover plate disposed behind the bezel. The bezel defines side walls and is adapted to be fixed to the load control device. The elongated rectangular opening extends along a vertical axis of the bezel. The operating knob is operable to vertically move along the length of the elongated opening. The cover plate is slidably coupled to the side walls of the bezel. The shaft of the operating knob is coupled to the cover plate, such that the cover plate is vertically movable with respect to the bezel. The cover plate covers the rear of the opening in all positions to which the cover plate can be moved by the operating knob.