title: Centering a document window
body: <p>I am writing a core data, document based app. I am trying to center the document's window. I have tried calling the following code from the document's makeWindowControllers method, from the window controller's awakeFromNib method and from the window controller's showWindows method. I keep getting a nil result for myWindow. Any ideas? Thank you.</p>
  
  <pre><code>NSWindow *myWindow = [myWindowController window];
  [myWindow center];
  </code></pre>