Webpart, persisting boolean properties

I've created a webpart with a lot of properties. All the properties (enums, strings) are persisted just fine when the following attributes are added:

    [Personalizable(PersonalizationScope.Shared)]
    [WebBrowsable(true)]

apart from the boolean properties. When the webpart is edited again the stored values for those properties aren't retrieved. Is this behaviour unique to boolean prop开发者_如何学Pythonerties?

The property definition is a plain, automatic bool property. In some cases the DefaultValue attribute is applied.

thanks