Logical color palettes cannot contain more entries than the color-depth of the video driver (for example, on a 256-color driver, you cannot call the BitBlt function with a color palette of more than 256).

The XGA video driver (and all based on it) cannot handle being passed a palette larger than 256 on a machine that has a color-depth of 256. It is possible to do this, but the video driver traps.