All fields must be part of field groups. The group is just a mechanism to treat multiple fields together as a unit in the DISPLAY statement. There is only one rule about the field positions of different groups: active fields must not overlap. Overlapping is acceptable among fields as long as they are not simultaneously active. Active fields are the ones that are specified together in the current DISPLAY statement.

You name groups specified in the WINDOW statement. You specify groups in the DISPLAY statement just by putting them in parentheses; they are not named.