A projection window operator providing horizontal displacement of a window relative to a vertical plane of the frame of the window. With at least one projection window operator installed on each of opposing sides of the window, the window can be actuated between a first closed position and second open position in which a trickle ventilation is provided around the window. The projection window operators installed on the window can be interconnected for simultaneous actuation, or actuated individually, providing selective ventilation on either side.