A collision area is a restricted area on the screen that cannot be overwritten by pointer drawing. Values contained in the data structure defining a collision area must be specified in either character or pel values, depending on the current display mode. If the collision area is defined as the entire screen, pointer drawing is disabled for the session.

The pointer is not drawn in this area until a different area is specified through another call to this function or until MOU_UNMARKCOLLISIONAREA is called.