When the terminal does not have a mouse, 
  uses the keypad  to simulate
one.
 MOUSE-MODE appears in the command/status window during this simulation.
To enter mouse  mode, press the
MOUSE
 MOUSE
 } key; to leave it, press DIAG
 DIAG
 }.
When the system is in mouse mode the screen cursor shows the position of the
 mouse cursor; the position of the  normal cursor
is remembered (though not shown) and is restored when mouse mode is left.
Only the keypad keys are meaningful in mouse mode,
and they have meanings similar to (though different from) their usual ones;
the exact meanings are given below.