public static void ShowTip(string tipMsg, int second = 15)
        {
            if (win == null)
            {
                win         = new TipWindow();
                win.Closed += Win_Closed;
                win.Show();
            }

            if (win.Visibility == Visibility.Collapsed)
            {
                win.Visibility = Visibility.Visible;
            }

            win.AddItem(tipMsg, second);
        }
 private static void Win_Closed(object sender, EventArgs e)
 {
     win = null;
 }