message: use offsetHeight for consistency with sizer
diff: @@ -191,7 +191,7 @@ module.exports = React.createClass({
  });
  this._layout.update(
  this._layoutSections,
  - this.resizeContainer && this.resizeContainer.clientHeight,
  + this.resizeContainer && this.resizeContainer.offsetHeight,
  );
  this._checkSubListsOverflow();
  