types
Annotation Type WidgetDef.Contained

@Retention(value=RUNTIME)
@Target(value=TYPE)
@Documented
public static @interface WidgetDef.Contained

Declare that a widget type cannot appear at the top level. For instance, a layout widget without a parent in which to put the child widgets is nonsensical. All widget types derived from this one will also be contained (in other words, the attribute is inherited).