title: display 2 cardlayout panel simultaneously after one another
body: <p>I want to display 2 cardlayout, the first one will be displayed then after some delay the second one will be displayed. I tried my code but It will skip the first one and directly display the second one.</p>
  
  <pre><code>CardLayout cardLayout = (CardLayout)mainpanel.getLayout();
  cardLayout.show(mainpanel, "card10");
  
  TimeUnit.SECONDS.sleep(15);
  cardLayout.show(mainpanel, "card11");
  </code></pre>