SimpleCommand usage

val body = VerticalLayout().apply {
    isSpacing = true

    val isButtonEnabledProperty = objectProperty(false)
    val isButtonVisibleProperty = objectProperty(true)

    val showHelloWorldCommand = SimpleCommand(
        action = { Notification.show("Hello World!!!") },
        isEnabledPredicate = { isButtonEnabledProperty.value },
        isVisiblePredicate = { isButtonVisibleProperty.value }
    ).apply {
        bindNotifier(isButtonEnabledProperty)
        bindNotifier(isButtonVisibleProperty)
    }

    this += CheckBox("Hello World enabled?", isButtonEnabledProperty).apply { isImmediate = true }
    this += CheckBox("Hello World visible?", isButtonVisibleProperty).apply { isImmediate = true }
    this += button("Hello World!!!", MadosTheme.FontIcons.SUBMIT, showHelloWorldCommand)
}
this += body
this.setExpandRatio(body, 1f)