Java JTree is mouse event on tree root

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;

public class Main {
   public static void main(String args[]) {
      final JFrame f = new JFrame("JTree Demo");
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      Container c = f.getContentPane();
      c.setLayout(new FlowLayout());
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
      DefaultMutableTreeNode c1 = new DefaultMutableTreeNode("A");
      DefaultMutableTreeNode c2 = new DefaultMutableTreeNode("B");
      DefaultMutableTreeNode c3 = new DefaultMutableTreeNode("C");
      root.add(c1);/*from   ww w  .  j  a v  a2s.  com*/
      root.add(c2);
      root.add(c3);

      c1.add(new DefaultMutableTreeNode("1"));
      c1.add(new DefaultMutableTreeNode("2"));

      c2.add(new DefaultMutableTreeNode("3"));
      c2.add(new DefaultMutableTreeNode("4"));

      c3.add(new DefaultMutableTreeNode("5"));
      DefaultMutableTreeNode n6 = new DefaultMutableTreeNode("6");

      c3.add(n6);

      JTree t = new JTree(root);


      c.add(new JScrollPane(t));
      f.pack();
      f.setVisible(true);
   }

   public static boolean isRootItemPosition(MouseEvent evt) {
      if (evt == null) {
         throw new NullPointerException("evt == null");
      }
      if (evt.getSource() instanceof JTree) {
         JTree tree = (JTree) evt.getSource();
         TreePath mousePath = tree.getPathForLocation(evt.getX(), evt.getY());
         if (mousePath != null) {
            Object root = tree.getModel().getRoot();
            Object mouseItem = mousePath.getLastPathComponent();
            if ((root != null) && (mouseItem != null)) {
               return root.equals(mouseItem);
            }
         }
      }
      return false;
   }
}