* @param cssClasses
* @param columns
* @return
*/
public MultipleSelectionElement addCheckboxesVertical(String name, String i18nLabel, FormItemContainer formLayout, String[] keys, String values[], String[] cssClasses, int columns) {
MultipleSelectionElement mse = new MultipleSelectionElementImpl(name, MultipleSelectionElementImpl.createVerticalLayout(name, columns));
mse.setKeysAndValues(keys, values, cssClasses);
setLabelIfNotNull(i18nLabel, mse);
formLayout.add(mse);
return mse;
}