Collect only the XY charts in the root's container tree.
The narrower counterpart of findCharts, kept because it is part of the adapter's public API and because "every XY chart" is still a question worth asking of a mixed root.
Collect only the XY charts in the root's container tree.
The narrower counterpart of findCharts, kept because it is part of the adapter's public API and because "every XY chart" is still a question worth asking of a mixed root.