private boolean heyThatsTooClose(Point2D p, Point2D q, double min) {
		return Math.abs(p.getX() - q.getX()) < min &&
			Math.abs(p.getY() - q.getY()) < min;
	}
If the mouse is over a picked vertex, drag all picked
vertices with the mouse.
If the mouse is not over a Vertex, draw the rectangle
to select multiple Vertices
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/event/mouse/JungPickingGraphMousePlugin.java