/**
  * Called whenever the value of the selection changes.
  *
  * @param e the event that characterizes the change.
  */
 public void valueChanged(final ListSelectionEvent e) {
   final int[] selectedRows = table.getSelectedRows();
   for (int i = 0; i < selectedRows.length; i++) {
     final int row = selectedRows[i];
     final DrillDownParameter.Type type =
         parameterTableModel.getParameterType(model.mapToModel(row));
     if (DrillDownParameter.Type.MANUAL == type) {
       setEnabled(true);
       return;
     }
   }
   setEnabled(false);
 }