TornadoFX View setup for custom DnD

DragAndDrop.kt

class DragAndDrop : View() {

    /***** Global Variables *****/
    private val tileBuilderController: TileBuilderController by inject()
    val workbenchController: WorkbenchController by inject()
    private val controller: TileGUIController by inject()

    var workArea: GridPane by singleAssign()
    var moduleBoxItems = mutableListOf<Node>()
    lateinit var gridInfo: GridInfo


    /***** View *****/
    override val root = stackpane {
        gridInfo = GridInfo(controller.useTileGrid(workbenchController.tile))
        workArea = passGridInfo(gridInfo)
        setPrefSize(1000.0, 650.0)

        borderpane {
            top {
                label(title) {
                    font = Font.font(22.0)
                }
                menubar {
                    menu("File") {
                        item("Quit").action {
                            Platform.exit()
                        }
                    }
                }
            }

            center = workArea

            right {
                vbox {
                    maxWidth = 300.0
                    drawer = drawer(side = Side.RIGHT) {
                        item("Small Modules", expanded = true) {
                            datagrid(tileBuilderController.tileList) {
                                maxCellsInRow = 2
                                cellWidth = 100.0
                                cellHeight = 100.0

                                cellFormat {
                                    graphic = it
                                }
                            }
                        }
                    }
                }
            }
        }

        pane {
            style {
                backgroundColor += c(0, 100, 100, 0.05)
            }
            isMouseTransparent = true
        }
        
        addEventFilter(MouseEvent.MOUSE_PRESSED, ::startDrag)
        addEventFilter(MouseEvent.MOUSE_DRAGGED, ::animateDrag)
        addEventFilter(MouseEvent.MOUSE_RELEASED, ::stopDrag)
        addEventFilter(MouseEvent.MOUSE_RELEASED, ::drop)
    }
    
    private fun startDrag(evt: MouseEvent) {
        controller.startDrag(evt)
    }
    private fun animateDrag(evt: MouseEvent) {
        controller.animateDrag(evt)
    }
    private fun stopDrag(evt: MouseEvent) {
        controller.stopDrag(evt)
    }
    private fun drop(evt: MouseEvent) {
        controller.drop(evt, this@TileGUI)
    }

    init {
        moduleBoxItems.addAll( tileBuilderController.tileList )
    }
    
}