public interface ListEntry extends Element
{
    ElementType TYPE = new ElementType( ListEntry.class );

    // *** Value ***

    ValueProperty PROP_VALUE = new ValueProperty( TYPE, "Value" );

    Value<String> getValue();
    void setValue( String value );
}

public interface ListEntryReadOnly extends ListEntry
{
    ElementType TYPE = new ElementType( ListEntry.class );

    // *** Value ***

    @ReadOnly

    ValueProperty PROP_VALUE = new ValueProperty( TYPE, ListEntry.PROP_VALUE );
}

// *** List ***
    
@Type( base = ListEntry.class, possible = { ListEntry.class, ListEntryReadOnly.class } )
@CustomXmlListBinding( impl = YourCustomBinding.class )
@XmlElementBinding
( 
    mappings = 
    {
        @XmlElementBinding.Mapping( element = "entry", type = ListEntry.class ),
        @XmlElementBinding.Mapping( element = "entry", type = ListEntryReadOnly.class ),
    }
)

ListProperty PROP_LIST = new ListProperty( TYPE, "List" );

ElementList<ListEntry> getList();

final SapphireAction deleteAction = action.getActionSet().getAction("Sapphire.Delete");
final ListSelectionService listService = action.getPart().service(ListSelectionService.class);
final Listener selectionListener = new FilteredListener<ListSelectionChangedEvent>() {
	@Override
	public void handleTypedEvent(final ListSelectionChangedEvent event) {
		if (listService.selection().size() == 1 && ListEntryReadOnly.TYPE == listService.selection().get(0).type()) {
			deleteAction.setEnabled(true);
			return;
		}
		deleteAction.setEnabled(false);
	}
};
listService.attach(selectionListener);

@Override
public boolean check(SapphireActionHandler handler) {
	return !handler.getAction().getId().equals("Sapphire.Add");
}

<action-handler-filter>
	<impl>com.foo.MyAddActionFilter</impl>
</action-handler-filter>