drop.kt

    /**
     * Compare selected dragging tile with the location of the drop
     * and render the module tile accordingly
     *
     * @property MouseEvent evt
     */
    private fun drop(evt : MouseEvent) {

        val mousePt = workArea.sceneToLocal( evt.sceneX, evt.sceneY )
        val targetNode = evt.target as Node
        val tileTarget = targetNode.findParentOfType(Tile::class)

        // if "Return to Workbench" is clicked, buttonTarget is assigned
        val buttonTarget = targetNode.findParentOfType(Button::class)

        if (::inFlightTileProperties.isInitialized && isDragAndDrop) {
            if (tileTarget is Tile && workArea.contains(mousePt) &&
                    inFlightTileProperties.title.toIntOrNull() == null) {
                pickGridTile(mousePt.x, mousePt.y)
                root.children[1].getChildList()!!.remove(inFlightTile)

                inFlightTileProperties.width = 100.0
                inFlightTileProperties.height = 100.0
                isDragAndDrop = false
            }

        }

        if (buttonTarget is Button && buttonTarget.textProperty().value == "Return to Workbench") {
            workbenchController.returnToWorkbench(this@TileGUI)
        }

        evt.consume()
    }