private static void SlideOutAnimation()
        {
            Backstage animBackstage = _animBackstage._backstage;

            animBackstage.IsHitTestVisible = false;

            animBackstage.PrepareToClose();

            DoubleAnimation transformAnim = new DoubleAnimation(-animBackstage.PART_ItemsStackPanel.ActualWidth, AnimationHelpers.AnimationDuration, FillBehavior.Stop);

            transformAnim.Completed += transformAnim_Completed;

            QuarticEase ease = new QuarticEase()
            {
                EasingMode = EasingMode.EaseInOut
            };

            DoubleAnimation opacityAnim = new DoubleAnimation(0, AnimationHelpers.AnimationDuration, FillBehavior.Stop);

            transformAnim.EasingFunction = opacityAnim.EasingFunction = ease;

            animBackstage.clientGridTranslate.BeginAnimation(TranslateTransform.XProperty, transformAnim);
            animBackstage.PART_ContentScreenshot.BeginAnimation(OpacityProperty, opacityAnim);
        }
        public ImportControl(Backstage backstage)
        {
            InitializeComponent();

            _backstage = backstage;
        }