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Displaying Selections
---------------------

The `j d' (`calc-show-selections') command controls how selected
sub-formulas are displayed.  One of the alternatives is illustrated in
the above examples; if we press `j d' we switch to the other style in
which the selected portion itself is obscured by `#' signs:

                3    ...                  #    ___
         (a + b)  . . .            ## # ##  + V c
     1*  ...............       1*  ---------------
             . . . .                   2 x + 1