/**
  * The disconnect method will stop the eventreplayer, and send null to the other peers, to stop
  * their reading from their streams. The GUI-menu is updated appropriately.
  */
 public void disconnect() {
   setTitle("Disconnected");
   active = false;
   if (connected == true) {
     er.stopStreamToQueue();
     ert.interrupt();
     setDocumentFilter(null);
     connected = false;
     setLocked(false);
   }
   deregisterOnPort();
   Disconnect.setEnabled(false);
   Connect.setEnabled(true);
   Listen.setEnabled(true);
   Save.setEnabled(true);
   SaveAs.setEnabled(true);
 }