The working list that contains the selected entries for the list box. The working list should contain only the code field that is specified in the multiSelectCodefield property. If allowMultiSelect is false or size is 1, this property is ignored.
Default value
Blank – only a single selection may be made in the list box.
Valid values
The name of a working list. Click the corresponding dropdown button in the property sheet to choose from a list of known working lists.