private void resetMarks() {
   interpToMark.removeAll();
   shiftToMark.removeAll();
   Iterator marks = mediator.getMarkerModel().getLabels().iterator();
   boolean hasMark = false;
   while (marks.hasNext()) {
     String mark = (String) marks.next();
     if (!ChronicleViewer.CURR_FRAME_LABEL.equals(mark)) {
       JMenuItem mi = new JMenuItem(mark);
       mi.addActionListener(itmAction);
       interpToMark.add(mi);
       mi = new JMenuItem(mark);
       mi.addActionListener(stmAction);
       shiftToMark.add(mi);
       hasMark = true;
     }
   }
   shiftToMark.setEnabled(hasMark);
   interpToMark.setEnabled(hasMark);
 }