private void NavBar_stpanel_MouseEnter(object sender, MouseEventArgs e)
        {
            DoubleAnimation an = new DoubleAnimation();

            an.From     = NavBar.Width;
            an.To       = 100;
            an.Duration = new Duration(TimeSpan.FromMilliseconds(250));
            NavBar.BeginAnimation(WidthProperty, an, HandoffBehavior.SnapshotAndReplace);
        }
        private void NavBar_stpanel_MouseLeave(object sender, MouseEventArgs e)
        {
            Trace.WriteLine(e.GetPosition(null).X);
            if (e.GetPosition(null).X < 20)
            {
                return;
            }
            DoubleAnimation an = new DoubleAnimation();

            an.From     = NavBar.ActualWidth;
            an.To       = 0;
            an.Duration = new Duration(TimeSpan.FromMilliseconds(250));
            NavBar.BeginAnimation(WidthProperty, an, HandoffBehavior.SnapshotAndReplace);
        }