/** @see org.eclipse.gef.commands.Command#execute() */
  @Override
  public void execute() {
    node.setX(newX);
    setLifeLineLayout();

    if (diagram != null) {
      SequenceUtil.refreshLifeLineOrder(diagram);
    }
  }
 /** @see org.eclipse.gef.commands.Command#redo() */
 @Override
 public void undo() {
   node.setX(oldX);
   unSetLifeLineLayout();
 }