>That will remove the highlight bar from the item, but what I want to do is select an item and have that item become unselectable again, ei grey out that item. My question was a little vague. Any idea how to do that?

Try:

IF MyListBox.ListItemID > 0
   MyListBox.Selected(MyListBox.ListItemID) = .F.
   MyListBox.ListItemID = -1
ENDIF