Produce a new column containing the difference between D and E. Then, create
a stacked column chart using Date, column D and the new (Difference) column.
Remove the border and fill for the D series, leaving only the difference
series illustrated on the chart as floating columns. Change date, along the
x-axis, to a category; otherwise, gaps are present for weekend days. Adding
B as a third (line) series involves specifying the source data which renders
another stacked column, selecting the added B column series and, using chart
type, re-typing B as a line chart.
> My data looks like this:
> Date B C D E
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>
> Then, I'd like to add a line, using column B, to the floating chart.