Scrollbar in Listbox not working
Heya, I suspect what might be happening is that your ListBox is expanding enough for every item however the ListBox is actually disappearing off the bottom of the Containing Control.
Does the ListBox actually stop properly or does it just seem to disappear? Try setting a MaxHeight on the ListBox and see if that makes the scrollbar appear. You should be able to set the VerticalScrollBarVisibility to Auto to have it only appear when needed.