When this happens, controls should explicitly check for a changed palette. Controls are encouraged to handle this message as well. The ambient palette property is useful only if a control needs to optimize its display to the palette of the container. If this is not necessary, the control should ignore the ambient palette property. Containers can use the return value to determine if a control is palette-aware.
Containers can also use the color information returned to choose what palette to realize.
The control is not palette-aware. The control is palette-aware but does not have a palette at this time. The control is palette-aware and has returned its palette to the container. The container can determine its palette independently of its controls. Realizing the Palette Older OLE guidelines allowed the UI active object to realize its own palette in the foreground.