The Overlay Plane Color Map Management Scheme

Many applications use the default X11 color map. A technicolor (color flashing) effect in the windows using the default color map occurs when a non-default color map is downloaded into the hardware color map that had previously contained the default color map.

Because so many applications use the default X11 color map, and because the HCRX family of graphics devices have two hardware color maps in the overlay planes, the behavior on these devices is to dedicate (that is, lock) one overlay hardware color map to always hold the default X11 color map. This means that the assigned default overlay hardware color map cannot have another color map downloaded to it. The other overlay hardware color map is available to applications that use color maps other than the default.