public static async Task FadeOutForRectagle(this FrameworkElement element, float seconds = 0.3f, bool keepMargin = true) { // Create the storyboard var sb = new Storyboard(); // Add fade in animation sb.AddFadeOutForRectagle(seconds); // Start animating sb.Begin(element); // Make page visible element.Visibility = Visibility.Visible; // Wait for it to finish await Task.Delay((int)(seconds * 1000)); }