title: React Router won't render pushed page after first navigation
body: <p>I have a React web app and I'm trying to use <a href="https://reacttraining.com/react-router/web/guides/quick-start" rel="nofollow noreferrer">React Router</a> to navigate between screens.</p>
  
  <p>This is the route configuration in the App component:</p>
  
  <pre><code>  render() {
      return (
        &lt;Router&gt;
          &lt;Switch&gt;
            &lt;Route exact path="/"&gt;
              &lt;MainScreen /&gt;
            &lt;/Route&gt;
  
            &lt;Router path="/about"&gt;
              &lt;About  /&gt;
            &lt;/Router&gt;
          &lt;/Switch&gt;
        &lt;/Router&gt;
      );
    };
  </code></pre>
  
  <p>Somewhere in <code>MainScreen</code> I navigate to the About component, and it works:</p>
  
  <pre><code>this.props.history.push("/about");
  </code></pre>
  
  <p>But when I try to navigate back to <code>MainScreen</code> from the <code>About</code> page by pushing "/", it changes the URL in the browser, but does not render <code>MainScreen</code> (I keep seeing the <code>About</code> page).</p>
  
  <p>I'm using <code>withRouter()</code> when exporting both <code>MainScreen</code> and <code>About</code>.</p>