MSG-PAGED-PREV-WHEEL (value 16438)

This event occurs when the user scrolls a wheelmouse upward or towards the computer screen. The expected behavior from the run-time system is to scroll the grid upwards, that is, to fill in items from the top of the grid. 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 for more information.