Time series chart in Reports 7.9

Hi is it possible to chart 2 pens from 2 different datasets on a time series chart?
I have 2 different tag query histories.
Datakey on chart options seems only let me choose 1 but when I drag the tag down to Pens it subscripts it with "datasource.pen but doesn’t show the required data

The classic chart can do this, but you’ll have to configure it all yourself. That is, not quite so easy.