code: public Layer getLayerAt(int index) {
  		org.geomajas.gwt.client.map.layer.Layer<?> layer = mapModel.getLayers().get(index);
  		if (layer instanceof org.geomajas.gwt.client.map.layer.VectorLayer) {
  			return new VectorLayer((org.geomajas.gwt.client.map.layer.VectorLayer) layer);
  		}
  		return new LayerImpl(layer);
  	}
docs: Return the layer at a certain index. If the index can't be found, null is returned.
  
  @param index
  The specified index.
  @return Returns the layer, or null if the index can't be found.