class My20View : View() {
    override val root = BorderPane()

    init {
        with (root) {
            setPrefSize(400.0, 400.0)

            left {
                label("I'm left")
            }

            right {
                label("I'm right")
            }

            center {
                style {
                    backgroundColor += Color.RED
                }
            }

            widthProperty().addListener { obs, old, new ->
                val sideWidth = new.toDouble() * 0.2
                (left as Region).prefWidth = sideWidth
                (right as Region).prefWidth = sideWidth
            }
        }

    }
}