Sets the background color for this CRichEditCtrl object.
Indicates if the background color should be set to the system value. If this value is TRUE, cr is ignored.
The requested background color. Used only if bSysColor is FALSE.
The background color can be set to the system value or to a specified COLORREF value.
For more information, see EM_SETBKGNDCOLOR message and COLORREF structure in the Platform SDK.