FieldDef object
This function sets the option for a series of mark fields. It specifies what to do when too many fields are marked (filled in). The Option parameter can have one of these values:
MO_SELECT_MANUALLY = 0
MO_SELECT_FIRST = 1
MO_SELECT_LEAST_FILLED_IN = 2
MO_SELECT_MOST_FILLED_IN = 3
MO_ILLEGAL_VALUE = 4
Note: Only for advanced users. Only available in the Manager module.