`droppedTilesMoveAwayWhenDragZoneDraggedOver()` causes choppy animation in Chrome: [SO Question](https://stackoverflow.com/questions/51374245/js-html5-drag-and-drop-custom-dock-effect-jumping-around-in-chrome)
droppedTilesMoveAwayWhenDragZoneDraggedOver()causes choppy animation in Chrome: SO Question