In EDT thread, Swing JFrame components are not getting painted in the frame, i.e. frame is empty, but frame gets successfully painted in main thread

Question

I am trying to display a swing dialog using JFrame, while being in EDT thread with the check of SwingUtilities.isEventDispatchThread(). When in main thread, the components get correctly painted by SwingUtilities.invokeLater() method, but when inside EDT thread, components added to the frame are not appearing. Below is the code:

    private void showDialog(String title) {
    frame = new JFrame();
    frame.setTitle(title);
    JPanel panel = new JPanel();
    panel.setLayout(new BorderLayout());
    JButton cancelLogin = new JButton("cancel login");
    cancelLogin.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent arg0) {
            fireLoginCanceledEvent();
            disposeFrame();
        }
    });
    JPanel bottomPanel = new JPanel();
    bottomPanel.add(cancelLogin);
    panel.add(bottomPanel, BorderLayout.SOUTH);
    JLabel info = new JLabel("login initiated...");
    panel.add(info, BorderLayout.NORTH);
    frame.getContentPane().add(panel);
    frame.setLocationRelativeTo(null);
    frame.setSize(300, 100);
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    frame.setVisible(true);
 }

   private synchronized void disposeFrame() {
        if (frame != null) {
          if (frame.isDisplayable()) {
            frame.dispose();
   }

   public void display() {
    if (SwingUtilities.isEventDispatchThread()) {
        showDialog(windowTitle); // Components not appearing
        frame.revalidate();
        frame.repaint();
    }  else {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                showDialog(windowTitle); // Components are correctly rendered
            }
        });
   }
  }