How to disable the new 2nd level navigation for portal_tabs in 5.2RC3?

Is there a way to disable the new 2nd navigation/menu introducted in 5.2RC3?
I can not find a related setting in the navigation control panel.

There should be another control panel (at the bottom)


<?xml version='1.0' encoding='UTF-8'?>
  <records interface="Products.CMFPlone.interfaces.controlpanel.INavigationSchema" prefix="plone">
    <value key="navigation_depth">0</value>