This variable relates to read-only entry fields. As of Version 8.1, read-only entry fields were changed to conform to standard Windows behavior in that the background color is always gray (regardless of the COBOL program's Color setting). If you need the ability to change the color of read-only entry fields, set the runtime configuration variable ECN_3699 to 0.
The default behavior will not allow color changes and matches Windows behavior: read-only entry fields have gray backgrounds.