Observe which window sent a Close() event
===

I have a short questions and even after a while of searching through the web I have not found the answer.
I have two windows in a WPF application. One window should just be hidden when the user closes it. When the main window is closed the complete application shall close. 

I used 

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            e.Cancel = true;
            Hide();
        }

inside the class of the second window and hoped it would just catch its Close() event but unfortunately it catches all Close() events.

How can I separate between the windows to handle the events independently?

Regards
Larimow 