Listbox Slider control
 

I'm using a listbox to select states and cities. [I'm not using the ActiveX
listbox because it needs to work in both PC and Mac environments.] Selecting
a state in one listbox populates the second (city) listbox, which has a
different size depending on the state. My problem is this:

If the last city I selected was Yuma Arizona, when I switch to Arkansas I
want the (alphabetized) city first up to be Alma -- which I can control by
putting a 1 in the cell link. But the slider on the right of the listbox is
halfway down the listbox instead of sitting up at the top.

How can I force the slider to the top?