A window pane is mounted in a closed position outside a window frame, commonly referred to as a frameless window, and is movable into open positions parallel to the closed position. The window pane can be slid into a fully open position. Sliding mechanisms are attached to the window pane. Swing arms connect the sliding mechanisms to the window frame. Control arms also connect the sliding mechanisms to the window frame. They determine the distance of and control the translation of the window pan from the closed position to the initial open position. A handle is attached to at least one of the sliding mechanisms or window pane. Latching mechanisms secure the handle in the open positions. The invention is designed so that a plurality of screens allows air flow through the window frame, preventing passage of insects or debris through the window frame.