Wpf Button Location

Question

hi everyone. i am building an application. i have a button on a window. When i click the button, i want a new window popsup. but new window must open behind button. As another way, when window popsup,button must been shown in front of the window. How can i success that? is that possible? Thanks in advance. My codes as follows, private void Topics_Click(object sender, RoutedEventArgs e) { TreeView tree = new TreeView(); tree.Top = 250; tree.Left = 30; tree.Show(); } http://www.freeimagehosting.net/image.php?de9869e063.jpg i want it looks like that thanks in advance