Each DirectDraw application that uses one or more monitors in full-screen exclusive mode must have a single focus window, which is the window that receives keyboard input.
Each device that is to hold a full-screen DirectDraw surface must be represented by a DirectDraw object and a device window. The device window is the one that is sized to fit the window and is put on top of all other windows.
For single-monitor applications, there is no distinction between the device and focus window. They are one and the same.For multiple-monitor applications, however, you need to set a device window for each monitor, and you have to let each DirectDraw object know about the application's focus window. The focus window can also serve as the device window for one of the monitors. Other device windows should be children of the focus window so that the application does not minimize when the user clicks on one of them.
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