title: Xamarin.Forms - Master/detail page and navigation history issue
body: <p>I have an app which uses masterdetail page to show menu in all page. The navigation is happened in two way in my app. one from the menu and second way from Dashboard. so if i navigate to another page, and then press "BACK" button, it closes the application. It does not remember the navigation history. 
  The master detail page is as below:</p>
  
  <pre><code> public class RootPage : MasterDetailPage
      {
          public RootPage ()
          {
              var menuPage = new MenuPage ();
  
              menuPage.Menu.ItemSelected += (sender, e) =&gt; NavigateTo (e.SelectedItem as MenuItem);
  
              Master = menuPage;
              Detail = new NavigationPage (new ContractsPage ());
          }
  
          void NavigateTo (MenuItem menu)
          {
              Page displayPage = (Page)Activator.CreateInstance (menu.TargetType);
              Detail =    new NavigationPage (displayPage);
              IsPresented = false;
          }
      }
  </code></pre>
  
  <p>so any ideas how to overcome this problem?</p>