entirely blank screen on JavaScript based websites when rendered in JPanel #495

public class NavigationPanel extends JPanel {
    private static NavigationPanel INSTANCE;

    public static NavigationPanel getInstance() {
        if (INSTANCE == null)
            INSTANCE = new NavigationPanel();

        return INSTANCE;
    }

    private NavigationPanel() {
        setLayout(new GridLayout(1,1));

        Thread browserThread = new Thread("BrowserThread") {
            @Override
            public void run() {
                try {
                    CefAppBuilder builder = new CefAppBuilder();
                    CefSettings settings = builder.getCefSettings();
                    settings.windowless_rendering_enabled = false;
                    //settings.log_severity = CefSettings.LogSeverity.LOGSEVERITY_VERBOSE;
                    settings.root_cache_path = new File("jcef-cache").getAbsolutePath();

                    CefBrowser browser = builder.build().createClient().createBrowser("https://navi.graphhopper.org/", false, false);
                    NavigationPanel.this.add(browser.getUIComponent());
                } catch (CefInitializationException | UnsupportedPlatformException | IOException | InterruptedException ex) {
                    ex.printStackTrace();
                }
            }
        };

        browserThread.start();
    }
}

public class SampleApp extends JFrame {
    private SampleApp() {
        getContentPane().add(NavigationPanel.getInstance());
        setSize(800, 600);
        setVisible(true);
    }

    public static void main(String[] args) {
        new SampleApp();
    }
}