title: MUI leftsidebar is not closing when clicking on Backdrop
body: <p>We have an <a href="https://codesandbox.io/s/zqw48u?file=/demo.tsx" rel="nofollow noreferrer">example</a> for drawer from material-ui.<br />
  But this drawer doesn't have backdrop when we open the left sidebar.  So I changed their code to get backdrop.<br />
  On <em>line 113</em>, we have <code>variant=&quot;persistent&quot;</code> so I changed this to <code>variant=&quot;temporary&quot;</code> to get backdrop effect.<br />
  But if we click on backdrop, left-sidebar is not closing. (You can test it here with my example : <a href="https://codesandbox.io/s/serene-framework-7wgiqs?file=/demo.tsx" rel="nofollow noreferrer">https://codesandbox.io/s/serene-framework-7wgiqs?file=/demo.tsx</a>, just click on menu icon, and you will see left-sidebar)</p>