Connecting Shapes & Showing Properties

To achieve the above, create a new module, use the Window component wizard to create a new window, with "ToolVisualizer" as the class name prefix, set dependencies on the Visual Library, Nodes API, and the Dialogs API, and then paste the code below into the TopComponent:

private final Scene scene;
private final LayerWidget layer;
private final LayerWidget connectionLayer;
//Constructor:
public ToolVisualizerTopComponent() {
    initComponents();
    ...
    ...
    ...
    scene = new Scene();
    layer = new LayerWidget(scene);
    connectionLayer = new LayerWidget(scene);
    scene.addChild(layer);
    scene.addChild(connectionLayer);
    scene.getActions().addAction(ActionFactory.createSelectAction(new SelectProvider() {
        @Override
        public boolean isAimingAllowed(Widget widget, Point point, boolean bln) {
            return true;
        }
        @Override
        public boolean isSelectionAllowed(Widget widget, Point point, boolean bln) {
            return true;
        }
        @Override
        public void select(Widget widget, Point point, boolean bln) {
            NotifyDescriptor.InputLine desc = new NotifyDescriptor.InputLine("Name:", "Set a Name");
            DialogDisplayer.getDefault().notify(desc);
            Shape shape = new Shape(desc.getInputText(), new Date());
            ShapeWidget tw = new ShapeWidget(scene, point, shape);
            layer.addChild(tw);
            scene.repaint();
            scene.validate();
        }
    }));
    jScrollPane1.setViewportView(scene.createView());
}
class Shape {
    String type;
    Date date;
    public Shape(String type, Date date) {
        this.type = type;
        this.date = date;
    }
    public Date getDate() {
        return date;
    }
    public void setDate(Date date) {
        this.date = date;
    }
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
}
class ShapeWidget extends IconNodeWidget {
    public ShapeWidget(Scene scene, Point loc, final Shape shape) {
        super(scene);
        setPreferredLocation(loc);
        setLabel(shape.getType());
        setImage(ImageUtilities.loadImage("org/vislib/scene/circlered.png", true));
        getActions().addAction(ActionFactory.createExtendedConnectAction(connectionLayer, new MyConnectProvider()));
        getActions().addAction(ActionFactory.createMoveAction());
        getActions().addAction(ActionFactory.createPopupMenuAction(new PopupMenuProvider() {
            @Override
            public JPopupMenu getPopupMenu(final Widget widget, Point localLocation) {
                JPopupMenu popup = new JPopupMenu();
                JMenuItem propsMenu = new JMenuItem("Properties");
                propsMenu.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        AbstractNode node = new AbstractNode(Children.LEAF) {
                            @Override
                            protected Sheet createSheet() {
                                Sheet sheet = super.createSheet();
                                Set set = sheet.createPropertiesSet();
                                set.put(new TypeProperty(shape));
                                set.put(new DateProperty(shape));
                                sheet.put(set);
                                return sheet;
                            }
                        };
                        node.setDisplayName(shape.getType());
                        node.setShortDescription("Description of " + shape.getType());
                        NodeOperation.getDefault().showProperties(node);
                    }
                });
                popup.add(propsMenu);
                return popup;
            }
        }));
    }
}
private static class TypeProperty extends PropertySupport.ReadOnly {
    private final Shape shape;
    public TypeProperty(Shape shape) {
        super("shapeType", String.class, "Type", "Displays shape type");
        this.shape = shape;
    }
    @Override
    public String getValue() throws IllegalAccessException, InvocationTargetException {
        return shape.getType();
    }
}
private static class DateProperty extends PropertySupport.ReadOnly {
    private final Shape shape;
    public DateProperty(Shape shape) {
        super("shapeDate", Date.class, "Date", "Displays shape date");
        this.shape = shape;
    }
    @Override
    public Date getValue() throws IllegalAccessException, InvocationTargetException {
        return shape.getDate();
    }
}
private class MyConnectProvider implements ConnectProvider {
    public boolean isSourceWidget(Widget source) {
        return source instanceof IconNodeWidget && source != null ? true : false;
    }
    public ConnectorState isTargetWidget(Widget src, Widget trg) {
        return src != trg && trg instanceof IconNodeWidget ? ConnectorState.ACCEPT : ConnectorState.REJECT;
    }
    public boolean hasCustomTargetWidgetResolver(Scene arg0) {
        return false;
    }
    public Widget resolveTargetWidget(Scene arg0, Point arg1) {
        return null;
    }
    public void createConnection(Widget source, Widget target) {
        ConnectionWidget conn = new ConnectionWidget(scene);
        conn.setTargetAnchorShape(AnchorShape.TRIANGLE_FILLED);
        conn.setTargetAnchor(AnchorFactory.createRectangularAnchor(target));
        conn.setSourceAnchor(AnchorFactory.createRectangularAnchor(source));
        connectionLayer.addChild(conn);
    }
}

That's all, now you can display the properties of the current widget and you're also able to connect widgets to each other.