/**
   * Refreshes the undo/redo icons with the last action performed.
   *
   * @param oUndoManager, the manager to use to check for undo/redo possibilities.
   */
  public void refreshUndoRedo(UndoManager oUndoManager) {

    // refresh undo
    pbUndo.setToolTipText(oUndoManager.getUndoPresentationName());
    pbUndo.setEnabled(oUndoManager.canUndo());

    // refresh redo
    pbRedo.setToolTipText(oUndoManager.getRedoPresentationName());
    pbRedo.setEnabled(oUndoManager.canRedo());
  }