add a button
clear the current dataset to avoid units errors. If the new dataset can be used, use it.
show the slice at the data point selected.
dispose of the popup slicer.
provide access to the dataset
the color for the mark (vertical bar) indicating slice position
provide the Y position of the data. Note this may be different than where the user requested because the nearest channel is provided.
set the color for the mark (vertical bar) indicating slice position Color(230,230,230) is the default.