New Post: A gray-ish area in the MessageBox.

I basically styled the MessageBox as shown here, but without the CloseButtonStyle. In the code-behind of my MainWindow.xaml, I have the following code:

private void Button_Click(object sender, RoutedEventArgs e)

    {
        MessageBoxResult result = Xceed.Wpf.Toolkit.MessageBox.Show("An error has ocurred.",     "Error", MessageBoxButton.OK, MessageBoxImage.Error);

    }

I was wondering what was causing the gray-area at the bottom of the MessageBox, rather than an aquamarine fill like the rest of the background.