Design the Scroll menu. This group of statements defines the selections under Scroll on the menu bar. If the quoted string in the ITEM statement is not a valid command, then the SELECTION= option corresponds to a subsequent SELECTION statement, which specifies a valid command.
menu s; item 'Next Obs' selection=n; item 'Prev Obs' selection=p; item 'Top'; item 'Bottom'; selection n 'forward'; selection p 'backward';