The following example uses ON( ) to display ON ERROR and ON KEY LABEL settings.
ON ERROR DO errorhand
ON KEY LABEL CTRL+F2 WAIT WINDOW 'You pressed ^F2'
ON KEY LABEL ALT+Z DISPLAY MEMORY
CLEAR
? ON('ERROR') && Displays DO errorhand
? ON('KEY', 'CTRL+F2') && Displays WAIT WINDOW 'You pressed ^F2'
? ON('KEY', 'ALT+Z') && Displays DISPLAY MEMORY
ON ERROR
ON KEY LABEL CTRL+F2
ON KEY LABEL ALT+Z