MASingleOptionDescription optionsAndLabels asDynamicObject d'ont work

> Hi All,
>
> i have one description based on MASingleOptionDescription.
>
> Now it work well when define the items with the options:
> [ MACityModel DataBase asArray] asDynamicObject.
>
> But because i need to view more text for any item in the list,
>     i define the options with the method
>
>     optionsAndLabels:[( MACityModel DataBase asArray) collect:[:itm|  
> Association key: itm value: itm display]] asDynamicObject
>
> With it the list is right create but d'ont update at " dynamic time  
> " with new item or change to MACityModel DataBase items.
>
> How i can solve my problem ?