code: function (items) {
          var self = this, settings = self.settings, firstClass, lastClass, firstItem, lastItem;
  
          firstClass = settings.firstControlClass;
          lastClass = settings.lastControlClass;
  
          items.each(function (item) {
            item.classes.remove(firstClass).remove(lastClass).add(settings.controlClass);
  
            if (item.visible()) {
              if (!firstItem) {
                firstItem = item;
              }
  
              lastItem = item;
            }
          });
  
          if (firstItem) {
            firstItem.classes.add(firstClass);
          }
  
          if (lastItem) {
            lastItem.classes.add(lastClass);
          }
        }
docs: Applies layout classes to the container.
  
  @private