Accessible lists are used by combo boxes as container for
the list items. The drafts::com::sun::star::accessibility::XAccessibleSelection interface is not
supported at the moment due to implementation problems. Selection of
items is handled by the items and the edit field of the combo box.
The ::AccessibleExtendedComponent interface contains
additional methods to those of the ::AccessibleComponent
interface. These methods provide more seldom used information. The
division into two interfaces allows classes to support the more
frequently used methods of the ::AccessibleComponent
interface and only support the ::AccessibleExtendedComponent
interface if that makes sense for the class.