title: App Bar becomes hidden when navigating away from a page, with its background the phone's theme (and not what is defined in app)
body: <p>When I'm navigating between pages on my WP8 app, I noticed as part of the transition animation (using Telerik's i.e. "RootFrame = new Telerik.Windows.Controls.RadPhoneApplicationFrame();"), the App Bar on the page navigated from becomes hidden first. It's sudden and for a very short amount of time, but is still noticeable. </p>
  
  <p>Here is the app bar of the page:</p>
  
  <p><img src="https://i.stack.imgur.com/0GCZA.png" alt="enter image description here"></p>
  
  <p>And here is the app bar of the same page when I hit back i.e. navigating away from it. Where the app bar was showing previously, there's a white background showing instead. Of course, as I said, this is for a split moment, because before you know it, you're taken back to the last page. But it's still noticeable.</p>
  
  <p><img src="https://i.stack.imgur.com/2UT34.png" alt="enter image description here"></p>
  
  <p>The white background appears to be that of the phone's theme (its theme is Light), even though I've reset the RootFrame's background to black in App.xaml.cs, and also reset all brushes to use the Dark theme's (advice from <a href="https://stackoverflow.com/questions/17582998/windows-phone-8-how-to-be-always-on-one-theme-even-if-phones-theme-changed">Windows phone 8 How to be always on one theme even if phone&#39;s theme changed</a>):</p>
  
  <pre><code>public App()
  {
      // code here
      RootFrame.Background = new SolidColorBrush(Colors.Black);
      DarkTheme();
  }
  public void DarkTheme()
  {
          ((SolidColorBrush)Resources["PhoneRadioCheckBoxCheckBrush"]).Color = ((SolidColorBrush)Resources["PhoneRadioCheckBoxBorderBrush"]).Color = ((SolidColorBrush)Resources["PhoneForegroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneBackgroundBrush"]).Color = Color.FromArgb(0xFF, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneContrastForegroundBrush"]).Color = Color.FromArgb(0xFF, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneContrastBackgroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneDisabledBrush"]).Color = Color.FromArgb(0x66, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneProgressBarBackgroundBrush"]).Color = Color.FromArgb(0x19, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextCaretBrush"]).Color = Color.FromArgb(0xFF, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneTextBoxBrush"]).Color = Color.FromArgb(0xBF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextBoxForegroundBrush"]).Color = Color.FromArgb(0xFF, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneTextBoxEditBackgroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextBoxReadOnlyBrush"]).Color = Color.FromArgb(0x77, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneSubtleBrush"]).Color = Color.FromArgb(0x99, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextBoxSelectionForegroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneButtonBasePressedForegroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextHighContrastBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextMidContrastBrush"]).Color = Color.FromArgb(0x99, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneTextLowContrastBrush"]).Color = Color.FromArgb(0x73, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneSemitransparentBrush"]).Color = Color.FromArgb(0xAA, 0x00, 0x00, 0x00);
          ((SolidColorBrush)Resources["PhoneChromeBrush"]).Color = Color.FromArgb(0xFF, 0x1F, 0x1F, 0x1F);
          ((SolidColorBrush)Resources["PhoneInactiveBrush"]).Color = Color.FromArgb(0x33, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneInverseInactiveBrush"]).Color = Color.FromArgb(0xFF, 0xCC, 0xCC, 0xCC);
          ((SolidColorBrush)Resources["PhoneInverseBackgroundBrush"]).Color = Color.FromArgb(0xFF, 0xFF, 0xFF, 0xFF);
          ((SolidColorBrush)Resources["PhoneBorderBrush"]).Color = Color.FromArgb(0xBF, 0xFF, 0xFF, 0xFF);
      }
  </code></pre>
  
  <p>The custom set RootFrame background and reset brushes in DarkTheme() seem to be working for the most part. It's only when transitioning from a non-default page (i.e. not the page the app lands on) with an app bar back to another page, that this problem seems to arise.</p>
  
  <p>Any ideas what's going on?</p>