title: React router always renders first route in nested component
body: <p>In the component rendered by react-router i have another routes. However, from these nested routes always only first route is rendered regardless actual path.
  I read about update blocking and tried to wrap components into withRouter() but it didnt help.</p>
  
  <p>I read about update blocking and tried to wrap components into withRouter() but it didnt help.
  Reordering routes gives the same behavior.</p>
  
  <p>App.js</p>
  
  <pre><code>class App extends Component{
      render() {
          return (
              &lt;div&gt;
                  &lt;Router&gt;
                      &lt;Switch&gt;
                          &lt;Route path="/login" component={Login} /&gt;
                          &lt;PrivateRoute path="/" component={Main}  /&gt;
                      &lt;/Switch&gt;
                  &lt;/Router&gt;
                  &lt;Modal /&gt;
              &lt;/div&gt;
          )
      }
  }
  </code></pre>
  
  <p>Main.js</p>
  
  <pre><code>class Main extends Component{
      render(){
          return (
              &lt;div className="full-height flex-container flex-column"&gt;
  
                  &lt;div style={{display: "flex", flexDirection: "row", height: "100%"}}&gt;
                      &lt;NavigationBar items={[{name: 'Categories', route: '/'}, {name: 'Products', route: '/products'}]} /&gt;
                      &lt;Content /&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
          )
      }
  }
  </code></pre>
  
  <p>Content.js and problematic routes itself</p>
  
  <pre><code>class Content extends Component{
      render(){
          return(
              &lt;div style={{ width: "100%"}}&gt;
                 &lt;Switch&gt;
                      &lt;Route exact to="/" component={CategoriesPage} /&gt;
                      &lt;Route to="/products" component={ProductsPage} /&gt;
                 &lt;/Switch&gt;
              &lt;/div&gt;
          )
      }
  }
  </code></pre>
  
  <p>I expect for path "/" - CategoriesPage to be rendered, and for "/products" - ProductsPage, but now CategoriesPage rendered for both "/" and "/products".
  Thanks in advance.
  Sample available here: <a href="https://codesandbox.io/s/github/nomernabis/login-flow-redux" rel="nofollow noreferrer">https://codesandbox.io/s/github/nomernabis/login-flow-redux</a>.</p>