Map waypoint info - display as non-modal dialog ?

I'm upgrading an app with a graph that illustrates a chemical process.

Whenever the user right-clicks a point on the graph, I want to display additional info -- just like when one clicks a waypoint in mapping software.

I've checked several charting libraries -- and JXMapKit -- that provide this functionality, but each limits other things the graph does.

In mapping apps, is this implemented as a non-modal dialog? or as, e.g., a JPanel painted in a layer of JLayeredPane?