if ( chosenConditionsSelection.getConstraintValueType() == BaseSingleFieldConstraint.TYPE_PREDICATE ) {
txtPredicateExpression.setText( chosenConditionsSelection.getFactField() );
}
ddOperator.addValueChangeHandler( new ValueChangeHandler<OperatorSelection>() {
public void onValueChange(ValueChangeEvent<OperatorSelection> event) {
chosenConditionsSelection.setOperator( event.getValue().getValue() );
final boolean requiresValueList = presenter.requiresValueList( availablePatternsSelection,
chosenConditionsSelection );