title: Content beneath app bar is not shrinking in material ui
body: <p>I have added two navBar one after another, where the top Nav bar has a side drawer where the content beneath inside is shrining on clicking toggle button. While in other hand i am displaying another Nav bar beneath first nav bar, it also has a side drawer but while toggling it the content inside is not shrinking. I have tried that in all possible ways. Pls help me to fix that. Here i ma sharing the code sandbox link for that.<a href="https://codesandbox.io/s/persistentdrawer-pygrt?file=/PersistentDrawer.js" rel="nofollow noreferrer">https://codesandbox.io/s/persistentdrawer-pygrt?file=/PersistentDrawer.js</a></p>
  
  <p>Thanks in advance</p>