model.addChild( new DefaultNode( "button2", Lookups.singletonLookup( Action.class, new GroupButtonAction( "button2" ) ) ) );
model.addChild( new DefaultNode( "button3", Lookups.dynamicLookup( new GroupButtonAction( "button3" ), new MyBasicGroupButtonPresenter() ) ) );
model.addChild( new DefaultNode( "button4", Lookups.singletonLookup( Action.class, new GroupButtonAction( "button4" ) ) ) );
Node child = model.getChildren().get( 3 );
if ( child.getLookup().lookup( Action.class ) == null ) {
throw new IllegalStateException( "uups" );
}
}