The EM_SETBKGNDCOLOR message sets the background color for a rich edit control.
EM_SETBKGNDCOLOR
wParam = (WPARAM) (BOOL) fUseSysColor;
lParam = (LPARAM) (COLORREF) clr;
Returns the old background color.
Windows NT: Requires version 3.51 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in richedit.h.
Rich Edit Controls Overview, Rich Edit Messages, COLORREF