如何使可编辑的JComboBox的输入框高亮显示？

 
    需要做一个可编辑的JComboBox，即可以在里面输入查找，也可以选择下拉框选择。但两者都必须在操作完后，comboBox的输入框都必须高亮显示，如图：
                                                  但是把鼠标点击输入框或者在里面输入数字按回车进行匹配时，都可是得输入框高亮显示，但是按那个下拉框按钮进行选择时却不能使其高亮显示，不知道怎么会事，希望高手指点。以下为测试代码：
package kissJava.JComboBox;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.util.Vector;
import javax.swing.ComboBoxEditor;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class EditComboBox{
     String labels[] = { "Chardonnay", "Sauvignon", "Riesling", "Cabernet",
                "Zinfandel", "Merlot", "Pinot Noir", "Sauvignon Blanc",
                "Syrah", "Gewurztraminer" };
      String code[] = { "1", "2", "3", "4","5", "6", "7", "8", "9", "10" };
     JComboBox comboBox =null;
     final KJComboBoxEditor kjce = new KJComboBoxEditor();
     public EditComboBox(){
          JFrame frame = new JFrame("Editable JComboBox");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          Container contentPane = frame.getContentPane();
          comboBox = new JComboBox();
          comboBox.setMaximumRowCount(5);  
          comboBox.setEditable(true);
          initCombox();  
          comboBox.setEditor(kjce);
          contentPane.add(comboBox, BorderLayout.NORTH);  
          final JTextArea textArea = new JTextArea();
          JScrollPane scrollPane = new JScrollPane(textArea);
          contentPane.add(scrollPane, BorderLayout.CENTER);
          ActionListener actionListener = new ActionListener() {
             public void actionPerformed(ActionEvent actionEvent) {
                  textArea.append("Selected: " + comboBox.getSelectedItem());
                  textArea.append(", Position: " + comboBox.getSelectedIndex());
                  textArea.append(System.getProperty("line.separator"));
                  comboBox.requestFocus();
                  kjce.selectAll();
             }
          };
         comboBox.addActionListener(actionListener);
         frame.setSize(300, 200);
         frame.setVisible(true);
  }
  private void initCombox(){
      final Vector<String> v = new Vector<String>(code.length);
      String[] str = new String[code.length];
      for(int i = 0,length = code.length; i<length;i++) {
              str[i] = code[i] + " - " + labels[i];
              v.add(str[i]);            
      }
      comboBox.setModel(new DefaultComboBoxModel(v));
  }
  public static void main(String args[]) {
    new EditComboBox();
  }
  class KJComboBoxEditor implements ComboBoxEditor {    
    JTextField jtf = new JTextField();    
    public KJComboBoxEditor(){
        jtf.addActionListener(new java.awt.event.ActionListener(){
            public void actionPerformed(ActionEvent e) {
                boolean isExit = false;
                String codeStr = jtf.getText().trim();
                for(int i = 0,length = code.length; i<length;i++) {
                     if(codeStr.equals(code[i])){
                        //jtf.setText(code[i] + " - " + labels[i]);
                         setItem(code[i] + " - " + labels[i]);
                         comboBox.setSelectedIndex(i);
                         isExit = true;
                     }                  
                }
                 if(!isExit){ 
                     jtf.setText(""); 
                 }
                 selectAll();                 
            }    
        });
    
        jtf.addMouseListener(new java.awt.event.MouseListener(){
            public void mouseClicked(MouseEvent e) {
                selectAll();
                comboBox.setPopupVisible(false);
            }
            public void mouseEntered(MouseEvent e) {    
            }
            public void mouseExited(MouseEvent e) {        
            }
            public void mousePressed(MouseEvent e) {
                selectAll(); 
                comboBox.setPopupVisible(false);
            }
            public void mouseReleased(MouseEvent e) {    
                selectAll(); 
            }        
        });
    }
    public void addActionListener(ActionListener l) {
    }
    public JTextField getEditorComponent() {
        return jtf;
    }
    public Object getItem() {        
        return jtf.getText();
    }
    public void removeActionListener(ActionListener l) {    
    }
    public void selectAll() {    
        jtf.selectAll();
        jtf.requestFocus();
        
    }
    public void setItem(Object anObject) {        
        jtf.setText(anObject.toString());
    }  
  }
}