protected ProgramNode getTreeNode(Point p) {
		TreePath path = getPathForLocation(p.x, p.y);
		if (path != null) {
			return (ProgramNode) path.getLastPathComponent();
		}
		return null;
	}
Get the node at the given point.
@param p the point
@return null if there is no node a the point p.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/DragNDropTree.java