code: protected ModalWindow newModalWindow(final String id, final IModel<T> model)
  	{
  		final ModalWindow modal = new ModalWindow(id, model);
  		return modal;
  	}
docs: Factory method for creating a new {@link ModalWindow}. This method is invoked in the
  constructor from the derived classes and can be overridden so users can provide their own
  version of a new {@link ModalWindow}.
  
  @param id
  the wicket id
  @param model
  the model
  @return the new {@link ModalWindow}.