title: ScrollView Frame.Navigate Null
body: <p>I am trying to navigate to a page from a ScrollViewer control:</p>
  
  <pre><code>  &lt;Button x:Name="btnViewMenu" Content="View Menu" Click="btnViewMenu_Click" Margin="0,20,0,0" CommandParameter="{Binding}" Grid.Row="3" /&gt;
  
   private void btnViewMenu_Click(object sender, RoutedEventArgs e)
      {
          Button btn = (Button)sender;
          RestaurantLocation loc = btn.CommandParameter as RestaurantLocation;
          App.CurrentRestaurantLocation = loc;
          this.Frame.Navigate(typeof(SearchFormPage));
      }
  </code></pre>
  
  <p>On the search form page, I get this error:</p>
  
  <p>_pageKey cannot be null:</p>
  
  <pre><code>    /// &lt;summary&gt;
      /// Invoked when this page will no longer be displayed in a Frame.
      /// &lt;/summary&gt;
      /// &lt;param name="e"&gt;Event data that describes how this page was reached.  The Parameter
      /// property provides the group to be displayed.&lt;/param&gt;
      protected override void OnNavigatedFrom(NavigationEventArgs e)
      {
          var frameState = SuspensionManager.SessionStateForFrame(this.Frame);
          var pageState = new Dictionary&lt;String, Object&gt;();
          this.SaveState(pageState);
          frameState[_pageKey] = pageState;
      }
  </code></pre>
  
  <p>Am I navigating improperly? This only happens inside of a scrollviewer.</p>