/** Updates the menu when the current database project is closed. */
  public void onDatabaseClose() {
    if (pbUndo != null) pbUndo.setEnabled(false);
    if (pbRedo != null) pbRedo.setEnabled(false);
    if (pbOpen != null) pbOpen.setEnabled(true);
    if (pbClose != null) pbClose.setEnabled(false);
    if (pbHelp != null) pbHelp.setEnabled(false);
    if (pbSearch != null) pbSearch.setEnabled(false);
    if (pbImageRollover != null) pbImageRollover.setEnabled(false);

    history.clear();
  }
 /** Clear the view history. */
 public void clearHistory() {
   history.clear();
 }