private void tableCellEditorChanged(Object from, Object to) {
      boolean editingStarted = from == null && to != null;
      boolean editingStopped = from != null && to == null;

      if (editingStarted) {
        activate();
      }
      else if (editingStopped) {
        deactivate();
      }
    }
private void tableCellEditorChanged(Object from, Object to)