public ObjectProperty<Location> currentLocationProperty() {
        if (null == currentLocation) {
            currentLocation = new ObjectPropertyBase<Location>(_currentLocation) {
                @Override protected void invalidated() { fireTileEvent(LOCATION_EVENT); }
                @Override public Object getBean() { return Tile.this; }
                @Override public String getName() { return "currentLocation"; }
            };
            _currentLocation = null;
        }
        return currentLocation;
    }
Defines an optional node that can be used in combination with the
CustomTileSkin.
@param GRAPHIC
src/main/java/eu/hansolo/tilesfx/Tile.java