UI Widget "Graph + Single Stat" with more than one data series

If you use a widget of the type Graph + Single Stat but have more than one data series in the graph, it seems to be left to chance which of these data series is then displayed as a numerical value in the Single Stat. You can’t set this anywhere either!?
It would be good if you could set this and if the colour of the numerical value is identical to the colour of the corresponding curve.
Feature Request?