PopupMenu.ListIndex Property
Syntax
ListIndex as Integer
Used to get or set the selected item number. The first item is numbered zero.
A value of -1 means no selection. May be set using the Properties pane to set the default value of PopupMenu control. If you use the InitalValue property to populate the PopupMenu control and set a value of ListIndex that corresponds to a default item, that item will be displayed in the IDE.