code: public List<?> getNotSelected() {
  		List options = getOptions();
  		if (options == null || options.isEmpty()) {
  			return Collections.EMPTY_LIST;
  		}
  
  		List notSelected = new ArrayList(options);
  		notSelected.removeAll(getSelected());
  		return Collections.unmodifiableList(notSelected);
  	}
docs: Returns the options which are not selected.
  
  @return The unselected options(s).