Stacking window manager

A stacking window manager (also called floating window manager) is a window manager that draws and allows windows to overlap, without using a compositing algorithm. All window managers that allow the overlapping of windows but are not compositing window managers are considered stacking window managers, although it is possible that not all use exactly the same methods. Other window managers that are not considered stacking window managers are those that do not allow the overlapping of windows, which are called tiling window managers.^[1]

Stacking window managers allow windows to overlap using clipping to allow applications to write only to the visible parts of the windows they present.

The order in which windows are to be stacked is called their z-order.