HelpNode polygonNode = new HelpNode("Polygon", builtinHelp.getURLValue("polygon"));
polygonNode.addHelpNode(new HelpNode("Set a regular polygon", builtinHelp.getURLValue("polygon_regular")));
polygonNode.addHelpNode(new HelpNode("Set a polygon specifing its coordinates", builtinHelp.getURLValue("polygon_set")));
polygonNode.addHelpNode(new HelpNode("Set polygon fill color", builtinHelp.getURLValue("polygon_fill")));
polygonNode.addHelpNode(new HelpNode("Set edges stroke and thickness", builtinHelp.getURLValue("polygon_edge")));
polygonNode.addHelpNode(new HelpNode("Convert polygon to lines", builtinHelp.getURLValue("polygon_convert")));
shapeFeatureNode.addHelpNode(polygonNode);
// Rectangle shape
HelpNode rectangleNode = new HelpNode("Rectangle", builtinHelp.getURLValue("rectangle"));