Normally -- as far as I know -- if you want the user to sort something, it's usually data in a report. APEX provides ways to do that. You can click on the report column header. I don't know of any standard feature to allow the user to sort an LOV -- but it would be an interesting feature.
- what sort options would you want: ascending, descending, other. .. ???
- where would they click to indicate how they wanted ascending, descending or other?