Thank-you whyisthisme. However, the problem remained after testing the
value using an if statement. as suggested. My code is now against the
Change Event on the radio-group (rather than the check-box itself), as
follows:-Floor.mandatory = (House.rawValue == 1) ? "disabled" :
"error";Floor.presence = (House.rawValue == 1) ? "invisible" :
"visible";Floor.rawValue = null;This works the same as described before,
with the Floor field being highlighted and a Mandatory Error message
appearing, BEFORE t...