This event occurs when the user scrolls a wheelmouse towards the computer screen. The expected behavior from the runtime is to scroll the list upwards, that is, to fill in items from the top of the list. EVENT-DATA-1 indicates if any virtual keys have been pressed at the same time as the scroll, and EVENT-DATA-2 indicates the number of lines that should be scrolled on each wheelmouse event. See MSG-PAGED-NEXT-WHEEL (value16439) for more information.