I have a graph with a number of data sets on it. For a certain printout I
needed one of the data sets not to show, so I selected the data series format
and chose 'none' for both line and marker. I then selected the entry in the
legend and selected 'clear' so it disappeared there.

Now I want it back! It is still showing up in the source data, but how do I
select it to bring back both the line and legend entry?