The name of the field in the listname working list that contains the name of the Webroutine that is to be invoked when a tree item is selected (the WAM containing the webroutine should be specified in list_onselect_wamname_field). This is only valid for unlevelled lists and will be ignored if listtype is "levelled".
Blank. The Webroutine specified by onselect_wrname will invoked.
The name of a valid field, in single quotes. A list of fields in the listname working list can be chosen from by clicking the corresponding dropdown button in the property sheet.