SET (INPUT_FOCUS_UNGRAB)

  Specifies the program or learn sequence DECTPU should execute whenever it
  processes a FocusOut event from DECwindows.

  Syntax

     SET (INPUT_FOCUS_UNGRAB, SCREEN [, {program_source | NONE}])

  Parameters

     SCREEN               A keyword used for compatibility with future
                          versions of DECTPU.

     program_source       A string, buffer, range, learn sequence, or
                          program specifying the ungrab routine.  If you do
                          not specify this parameter, DECTPU deletes the
                          current input focus ungrab routine; thereafter,
                          your application is not informed when DECTPU
                          processes a FocusOut event from DECwindows.

     NONE                 A keyword instructing DECTPU to delete the current
                          input focus ungrab routine.