Circle ring = new Circle(50, Color.RED);
kiht1.getChildren().add(ring);
kiht1.addEventFilter(MouseEvent.ANY, event -> event.consume());
ring.setOnMouseClicked(event -> {
    if (ring.getFill() == Color.RED)
        ring.setFill(Color.BLUE);
    else
        ring.setFill(Color.YELLOW);
});