[Magritte] default value again

Hello,

I have folllowing the exercises of Magritte
(http://www.lukas-renggli.ch/smalltalk/magritte) but I can't set the
default value of nationality field.
Here my code:

descriptionNationality
    ^ (MASingleOptionDescription auto: 'nationality' label:
'Nationality' priority: 55)
        options: #( 'France' 'England' 'Switzerland' 'Span' );
        default: 'Switzerland';
        beSorted;
        yourself

Somthing strange is that I have 2 selected option blanck.
I have try to do this with Title option and it work.:

descriptionTitle
    ^ (MASingleOptionDescription auto: 'title' label: 'Title' priority: 10)
        options: #( 'Mr.' 'Mrs.' 'Ms.' 'Miss.' );
        default: 'Mrs';
        yourself.

If somone know what is going wrong :-\ ...

Thanks.