class MainView : Fragment("My View") {
    val expandedState: ExpandedStateHolder by inject()

    override val root = listview(listOf(Category("A"), Category("B")).observable()) {
        cellCache {
            TitledPane(it.name,
                    listview(it.components) {
                        prefHeight = 200.0
                        cellCache {
                            stackpane {
                                this += ComponentView(it.name)
                            }
                        }
                    }).apply {
                val expandedState = expandedState.categoryExpanded(it.name)
                isExpanded = expandedState.value
                expandedState.cleanBind(expandedProperty())
            }
        }
    }

}