docs: function moveList( collapsedList, expandedList ) {
      const
          rect = collapsedList.getBoundingClientRect(),
          left = rect.left;
      let top = rect.top;
      while ( top <= 0 ) top += ITEM_HEIGHT;
      Dom.css( expandedList, {
          left: `${left}px`,
          top: `${top}px`
      } );
  }