_overflowItems() {
      if (this.items.length < 2) {
        // no need to overflow avatars
        return;
      }
      let hiddenItems = 0;
      for (let index = 0; index < this._itemsCount; index++) {
        const item = this.items[index];
        // show item to determine if it will fit the new container size
        item.hidden = false;
        // container width to current item + item width (avatar)
        // used to determine whether the following items will fit the container or not
        let totalWidth = this._getWidthToItem(item) + item.offsetWidth;
        if (index !== this._itemsCount - 1 || this._customOverflowButton) {
          totalWidth += this._overflowButtonEffectiveWidth;
        }
        if (totalWidth > this.offsetWidth) {
          hiddenItems = this._itemsCount - index;
          break;
        }
      }
      // hide the items that did not fit the container size
      this._setHiddenItems(hiddenItems);
    }
Overflows items that were not able to fit the container
@private