Three plots have been added, the middle plot will have connections to the top plot as well as separate connections to the bottom plot.Select the two top plots.Canvas->Add Hidden Plot...Deselect the "Y Axis" binding, because often the middle plot would have different Y units.Select the hidden plot element. (Autoplot 20160226 or newer)Add the plot element.The events bar plot element spans the two plots.Select the two bottom plots...Add add another hidden plot to contain the bottom events bar.Make sure the hidden inactive plot element is selected.Specify the two-event dataset for this plot element.This finishes. Note all five (three visible, two hidden) are all have x-axes bound together.