/** Remove all messages from the table (but leave "most recent") */
 public void clearAll() {
   int last_row = data.size() - 1;
   if (last_row > 0) {
     data.removeAllElements();
     SOAPMonitorData soap = new SOAPMonitorData(null, null, null);
     data.addElement(soap);
     if (filter_data != null) {
       filter_data.removeAllElements();
       filter_data.addElement(soap);
     }
     fireTableDataChanged();
   }
 }