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Full-screen is a feature provided by the operating system that allows a user to toggle an application into a special state where the application can access VGA graphics hardware directly. This is a key feature for games and other graphics-focused applications that require high performance. Also, it is often used by developers for text editing since it enables very fast text scrolling.

In a multiple monitor environment, only one graphics device can be VGA compatible. This is a limitation of computer hardware which requires that only one device respond to any hardware address. Because the VGA hardware compatibility standard requires specific hardware addresses, only one VGA graphics device can be present in a machine and only this device can physically respond to VGA addresses. Thus, applications that require going full screen will only run on the particular device that supports VGA hardware compatibility.