I want the user to be able to open a window from another xib file by clicking a button. I created an NSWindowController subclass. It has an open: action connected to the button, its window is connected to the window, and it is the File Owner of the xib containing the window. The open: method calls loadWindow and showWindow:, but the window does not appear. The problem appears to be that the window variable shows up as 0x0. Why is it nil, and how can I fix it? P.S. I know that I have been using this forum as a crutch for what I do not know about development. Please bear with me, as I am coming from iPhone programming - where I insisted on programmatically creating interfaces.