Java SE (Java Platform, Standard Edition)

I know that a node's requestFocus() method doesn't work until -

• it is visible,
• disableProperty() is set to false, and
• a scene owns it

but, if it is like this:

    TextField tf = new TextField(), tf2 = new TextField(), tf3 = new TextField();
    VBox holder = new VBox(5, tf, tf2, tf3);
    TitledPane tp = new TitledPane("Testing",holder);
    AnchorPane root = new AnchorPane(tp);

    @Override
    public void start(Stage primaryStage) {
        tp.setExpanded(false);
        tp.expandedProperty().addListener((c,o,n)->{
            if(n)
                tf.requestFocus();
        });
        Scene scene = new Scene(root, 300, 250);
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String[] args) {
        launch(args);
    }

then, all of the above is fulfilled but, still, textfield doesn't get focus if I expand the TitledPane.

Also, this doesn't seem to work:

Platform.runlater(()->tf.requestFocus());

Could anybody help me?