is lock cursor of any use whatsoever?

[Bill Marriott]

Richmond,

>>>
when I made a stack with a button with the following
script:

on mouseUp
  set the cursor to none
end mouseUp

and clicked on the button - nothing happened: Oh Dear.
<<<

Of course not. The handler exits and the usual cursor is restored. Try:

on mouseUp
  set the cursor to none
  wait 5 seconds
  beep
end mouseUp

You'll see the cursor disappear for five seconds.