Windows Phone 8.1 Light theme page with black background - xaml

Question

On WP (Windows Runtime App in my case), if we set the app to be running on Light theme, while the transition is performed, we can still see a black background.
Is there any way to avoid that?
For example, in the animation below, you can see that the page animates but before it ends there is a black background still. I'd like to set that to white somehow, but I am not sure how...
(Image from http://jamescroft.co.uk/blog/windows-phone/utilizing-page-transition-animations-in-windows-phone-8-1-apps/#comment-907).

Answer 1

After thinking a little bit on what item could be parent of Page, I turned my attention towards Frame.
This could be solved by setting the BackgroundColor property of the Frame, when it is created, in the OnLaunchedmethod (App.xaml.cs):
protected override async void OnLaunched(LaunchActivatedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
// Do not repeat app initialization when the Window already has content,
// just ensure that the window is active
if (rootFrame == null)
{
// Create a Frame to act as the navigation context and navigate to the first page
rootFrame = new Frame
{
CacheSize = 1,
Background = new SolidColorBrush(Colors.White)
};
if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
{
// TODO: Load state from previously suspended application
}
// Place the frame in the current Window
Window.Current.Content = rootFrame;
}
... //rest of OnLaunched method
}
Also you have to make sure to set the background of the Frame as well in the OnActivated method, since this will be launched in some cases where e.g. other apps launch URI to your app or Cortana launches the app, etc.