title: How to keep the popup menu of a JComboBox open on populating it?
body: <p>I have a JComboBox on my Panel. One of the popup menu items is 'More' and when I click that I fetch more menu items and add them to the existing list. After this, I wish to keep the popup menu open so that the user realizes that more items have been fetched however, the popup closes. The event handler code I am using is as follows</p>
  
  <pre><code>public void actionPerformed(ActionEvent e)
      {
          if (e.getSource() == myCombo) {
              JComboBox selectedBox = (JComboBox) e.getSource();
              String item = (String) selectedBox.getSelectedItem();
              if (item.toLowerCase().equals("more")) {
                  fetchItems(selectedBox);
              }
              selectedBox.showPopup();
              selectedBox.setPopupVisible(true);
          }
      }
  
  
  
  private void fetchItems(JComboBox box)
      {
          box.removeAllItems();
          /* code to fetch items and store them in the Set&lt;String&gt; items */
          for (String s : items) {
              box.addItem(s);
          }
      }
  </code></pre>
  
  <p>I do not understand why the showPopup() and setPopupVisible() methods are not functioning as expected.</p>