as
       * dropdowns within dropdowns are handled well.
       *
       * @param {HTMLElement} element The element that should lock scroll.
       */
      pushScrollLock: function(element) {
        // Prevent pushing the same element twice
        if (this._lockingElements.indexOf(element) >= 0) {
          return;
        }

        if (this._lockingElements.length === 0) {
          this._lockScrollInteractions();
        }

        this._lockingElements.push(element);

        this._lockedElementCache