The framework calls this member function for all top-level windows after the window with input focus has realized its logical palette, thereby changing the system palette.
This call allows a window without the input focus that uses a color palette to realize its logical palettes and update its client area.
The OnPaletteChanged member function is called for all top-level and overlapped windows, including the one that changed the system palette and caused the WM_PALETTECHANGED message to be sent. If any child window uses a color palette, this message must be passed on to it.
To avoid an infinite loop, the window shouldn't realize its palette unless it determines that pFocusWnd does not contain a pointer to itself.
This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.