Stacking window manager

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

Microsoft kept the stacking window manager up through Windows XP, which presented severe limitations to its ability to display 3D-accelerated content inside normal windows.

Although it was technically possible to produce some visual effects using third-party software.

[4] From Windows Vista onward, a new compositing window manager is the default on compatible systems.

Interacting with objects outside the original area of the foreground window might also be impossible, since the window manager would not be able to determine what the user is seeing, and would pass such mouse clicks to whatever programs occupied those areas of the screen during the last stacking event.