SET(ACTIVE_AREA)

  Designates the specified area as the "active area" in a DECTPU
  window.  The active area is the region in the window in which DECTPU
  ignores
  movements of the pointer cursor for purposes of distinguishing clicks
  from drags.  When the user presses down a mouse button,
  DECTPU interprets the event as a click if the upstroke occurs
  in the same active area as the down click.
  If the upstroke
  occurs outside the active area where the down click occurred,
  DECTPU interprets the event as a drag operation.

  Syntax

     SET (ACTIVE_AREA, window, column, row [,width, height])

  Parameters

     window               The window in which you want to define the active
                          area.

     column               An integer specifying the leftmost column of the
                          active area.

     row                  An integer specifying the topmost row of the
                          active area.
                          If you use 0, the active area row is the status
                          line, and
                          you cannot designate an area height greater than
                          1.)

     width                an integer specifying the width in columns of the
                          active area.  Defaults
                          to 1.)

     height               An integer specifying the height in rows of the
                          active area.  Defaults
                          to 1.)

  Example

     The following statement defines an active area two columns wide and
     three rows high in the current window:

     SET (ACTIVE_AREA, CURRENT_WINDOW, the_column, the_row, 2, 3);