An application sends a ZGM_SETGRIDBGCOLOR message to set the grid background color to the specified ZeeGrid color palette entry.
ZGM_SETGRIDBGCOLOR
wParam = (WPARAM)(int) iCPIndex; //index of the color palette to use for the grid background color
lParam = 0; //not used; must be zero
This message does not return a value
The grid background color is specifies the color of the grid body that is not occupied by grid cells. This is the area to the right of the rightmost column, and below the last row. This area will not gray when when grid has lost focus if using ZGM_GRAYBGONLOSTFOCUS.