private void popupHelp() {
    final JButton tempB = m_helpB;
    try {
      tempB.setEnabled(false);
      // Modified by Zerbetto
      //InputStream inR = 
      //	ClassLoader.
      //        getSystemResourceAsStream("weka/gui/beans/README_KnowledgeFlow");
      InputStream inR = this.getClass().getClassLoader()
                            .getResourceAsStream("weka/gui/beans/README_KnowledgeFlow");

      // end modifications
      StringBuffer helpHolder = new StringBuffer();
      LineNumberReader lnr = new LineNumberReader(new InputStreamReader(inR));
      
      String line;
      
      while ((line = lnr.readLine()) != null) {
	helpHolder.append(line+"\n");
      }
      
      lnr.close();
      final javax.swing.JFrame jf = new javax.swing.JFrame();
      jf.getContentPane().setLayout(new java.awt.BorderLayout());
      final JTextArea ta = new JTextArea(helpHolder.toString());
      ta.setFont(new Font("Monospaced", Font.PLAIN, 12));
      ta.setEditable(false);
      final JScrollPane sp = new JScrollPane(ta);
      jf.getContentPane().add(sp, java.awt.BorderLayout.CENTER);
      jf.addWindowListener(new java.awt.event.WindowAdapter() {
        public void windowClosing(java.awt.event.WindowEvent e) {
	  tempB.setEnabled(true);
          jf.dispose();
        }
      });
      jf.setSize(600,600);
      jf.setVisible(true);
      
    } catch (Exception ex) {
      tempB.setEnabled(true);
    }
  }