Code to reproduce :
 
    @Override
    public void start(Stage stage) throws Exception {
        final String STYLE = "-fx-fill: green;"
                                     + "-fx-stroke: red;"
                                     + "-fx-stroke-width: 6;"
                                     + "-fx-stroke-type: inside;";
        BorderPane root = new BorderPane();
        final QuadCurve cubic1 = getCubic();
        final QuadCurve cubic2 = getCubic();
        cubic2.setStyle(STYLE);

        ScheduledExecutorService service = Executors.newScheduledThreadPool(1);
        service.schedule(new Runnable() {
            @Override
            public void run() {
                Platform.runLater(new Runnable() {
                    @Override
                    public void run() {
                        cubic1.setStyle(STYLE);
                    }
                });

            }
        }, 5, TimeUnit.SECONDS);


        VBox panel = new VBox(30);
        panel.getChildren().addAll(new Button("Button"), cubic1, cubic2);
        root.setCenter(panel);
        Scene scene = new Scene(root, 600, 300);
        stage.setScene(scene);
        stage.setTitle(VersionInfo.getRuntimeVersion());
        stage.show();
    }