private void PopupWinButton_Click(object sender, RoutedEventArgs e)
{
PopUpWin win = new PopUpWin();
win.Owner = this;
win.Show();
}
private void TopmostForm_Shown(object sender, EventArgs e)
{
PopUpWin win = new PopUpWin();
WindowInteropHelper interopHelper = new WindowInteropHelper(win);
interopHelper.Owner = this.Handle;
win.Show();
}