MASingleOptionDescription with add button

Hello All, i have one description based on MASingleOptionDescription:linkDescription ^(MASingleOptionDescription new) reference: MANazionalityModel description; selectorAccessor: 'nazione'; options: [MANazionalityModel DataBase asArray] asDynamicObject ; label: 'Nazione'; beSorted; beRequired; beEditable; beSearchable; priority: 40; yourself Now my questions are:1) In the rendering of it, where i can select one option, i can manage add buttons to add new element to options ? 2) reference: MANazionalityModel description What's the sense of this declaration? When define MANazionalityModel descriptionWithOnlyOneDescription the system d'ont answer well ? Thanks,Dario