function refreshWorld(theItem) {
            if (_this.collectionMode) {
                _this.world.arrange({
                    immediately: theItem.options.collectionImmediately,
                    rows: _this.collectionRows,
                    columns: _this.collectionColumns,
                    layout: _this.collectionLayout,
                    tileSize: _this.collectionTileSize,
                    tileMargin: _this.collectionTileMargin
                });
                _this.world.setAutoRefigureSizes(true);
            }
        }
Raised when an error occurs while adding a item.
@event add-item-failed
@memberOf OpenSeadragon.Viewer
@type {object}
@property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised the event.
@property {String} message
@property {String} source
@property {Object} options The options passed to the addTiledImage method.
@property {?Object} userData - Arbitrary subscriber-defined object.