Enable legend in serial chart with only one series present
You should be able to add a side legend to a Serial Chart that has only one series, so that it behaves the same as a Serial Chart with multiple series. Currently the legend option only appears when you have more than one series in the chart.
If you have a collection of Serial Chart elements laid out vertically one above the other, and some are single series and some have multiple series, and you have side legends enabled for the multiple series charts, then their X-axis will be of different lengths. That difference in X-axes' lengths makes it difficult to visually compare the charts to see what lines up with what vertically.
By enabling the side legend for a Serial Chart that only has one series, then it too will have an X-axis that is shortened to make room for the side legend, then everything will align correctly vertically across all the Serial Chart elements.
For example, in the Dashboard below all the data is using the same time range for its X-axis, but various parameters have been group together in different Serial Charts. Because the top Serial Chart only has one series in it, you cannot turn on the side legend, so its X-axis values do not align with charts below it.
