Swing与JavaFX混合开发多次创建JFXPanel出现空指针与界面冻结问题

我有一个继承自Application的类：

public class IO extends Application {
    private static JFrame frame = new JFrame("Shapes");;
    private final JPanel content = new JPanel();
    private final JPanel drawingArea = new JPanel();

我的main/start方法代码如下：

public static void main(String[] args) {
    Application.launch(args);
}

public void start(Stage primaryStage) throws Exception {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            new JFXPanel(); // 初始化JavaFX环境
            createGUI();
        }
    });
}

我参考了现有方案处理Swing与JavaFX组件的兼容问题。但现在点击按钮向JPanel添加JPanel或JFXPanel时，添加JFXPanel的操作第一次正常，后续再次尝试生成JFXPanel就会失败，抛出Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException异常（实际第三次点击才会出现报错，第二次点击要么界面冻结要么无响应）。按钮的相关代码如下：

JButton go = new JButton("Go");
go.addActionListener(new ActionListener() {
    // 不相关代码
        System.out.println("Shape set parameters: " + selectedShape.setParameters(shapeParams));
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new JFXPanel(); // 初始化JavaFX环境
                Component shapePanel = (Component) new PaintedShape(selectedShape).getPanel();
                drawingArea.add(shapePanel);
                // drawingArea.add(new JLabel("Test"));
                // drawingArea.repaint();
                shapePanel.repaint();
                shapePanel.validate();
                drawingArea.repaint();
                drawingArea.validate();
                frame.pack();
                frame.setSize(new Dimension((int) (frame.getSize().getWidth() + PaintedShape.size.getWidth()),
                        (int) (frame.getSize().getHeight() + PaintedShape.size.getHeight())));
                frame.setLocationRelativeTo(null);
            }
        });
    }
});
params.add(go);
content.validate();

我多次调用validate()是因为之前偶尔会出现添加图形失败的问题，某一次加了这些调用后临时解决了该问题。希望能额外说明应该在哪个面板上调用这个方法更合理。完整代码已上传至GitHub仓库。

编辑：完整堆栈跟踪如下：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.sun.javafx.tk.quantum.QuantumToolkit.isSupported(QuantumToolkit.java:1153)
    at com.sun.javafx.application.PlatformImpl.isSupportedImpl(PlatformImpl.java:809)
    at com.sun.javafx.application.PlatformImpl.isSupported(PlatformImpl.java:482)
    at javafx.application.Platform.isSupported(Platform.java:168)
    at javafx.scene.shape.Shape3D.<init>(Shape3D.java:74)
    at javafx.scene.shape.Cylinder.<init>(Cylinder.java:89)
    at shapes.PaintedShape.painted3DShapePanel(PaintedShape.java:96)
    at shapes.PaintedShape.<init>(PaintedShape.java:51)
    at shapes.IO$1$1$1.run(IO.java:215)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

编辑：进一步调试发现，PaintedShape.java中无法实例化新的JavaFX 3D图形（见堆栈跟踪第6行at javafx.scene.shape.Shape3D.<init>(Shape3D.java:74)），可能是线程安全问题。我将JFXPanel生成代码嵌套了如下的Runnable结构后问题缓解，暂不清楚具体原理：

Platform.runLater(() -> {
    try {
        SwingUtilities.invokeLater(() -> {
            drawingPanel.add(shapePanel);
            frame.pack();
        });

    } catch (Exception e) {
        e.printStackTrace();
    }
});

内容的提问来源于stack exchange，提问作者ganondork