code: function(offset, boxes) {
  		var newBoxes = [];	// Must be careful to not overwrite references to the original ones.
  		for (var i=0; i<boxes.length; i++) {
  			newBoxes.push( this._positionBox( offset, boxes[i] ) );
  		}
  		return newBoxes;
  	}
docs: Adds the coordinate of the layer (in pixels / map canvas units) to each box coordinate.