@Override
	public void setGraphDisplayListener(GraphDisplayListener listener) {
		if (this.listener != null) {
			// This is a bit odd to do here, but this seems like the easiest way to cleanup any
			// previous listener when reusing the graph display.
			this.listener.dispose();
		}
		this.listener = listener;
	}
Gather all source and target vertices until there are no more available.
@return all the vertices in the component(s) of the selected vertices
Ghidra/Features/GraphServices/src/main/java/ghidra/graph/visualization/DefaultGraphDisplay.java