In a list box if you selected something and you want the data relevant to the selection be at the top how do you do that?
I don't understand a question. If you select a value in a listbox then by default the not data relevant to the selection will not be visible at all. You should see only data relevant to the selection.
If you mean sorting of the values within the listbox then look on the tab sorting and enable sorting to state and maybe further sorting-options.
might these option helps you?
see the attachment
Retrieving data ...