These are the actions to be taken by Intuition after the hook returns.
Set or clear these bits in SGWork structure Actions field.  A number of
these flags may already be set when the hook is called.


  Actions Flag    Purpose
  ------------    -------
  SGA_USE         If set, use contents of SGWork.
  SGA_END         Terminate gadget, Code field is sent to application
                  in IDCMP_GADGETUP event code field.
  SGA_BEEP        Beep (i.e., flash) the screen.
  SGA_REUSE       Reuse the input event.  Only valid with SGA_END.
  SGA_REDISPLAY   Gadget visuals have changed, update on screen.
  SGA_NEXTACTIVE  Make next possible gadget active (new for V37).
  SGA_PREVACTIVE  Make previous possible gadget active (new for V37).