title: NSDocument subclass instance apparently not in responder chain
body: <p>I'm creating my first NSDocument based application. I'm able to create new documents, both from scratch and by importing legacy files.</p>
  
  <p>This app will allow multiple windows per document, so I am overriding makeWindowControllers. This method is currently very simple:</p>
  
  <pre><code>- (void) makeWindowControllers
  {
      if (documentDatabase == nil) return;
      DataSheetWindowController * dswc = [[DataSheetWindowController alloc] initWithDatabase:documentDatabase];
      [self addWindowController: dswc];
  }
  </code></pre>
  
  <p>The window appears as expected, however, the Save, Revert to Save, and other document enabled menus are disabled, as if the document was not in the responder chain.</p>
  
  <p>As an experiment, I tried adding this method to my NSWindowController class:</p>
  
  <pre><code>- (void)saveDocument:(id)sender {
      [[self document] saveDocument:sender];
  }
  </code></pre>
  
  <p>With this method in place, the Save menu item is enabled, and selecting it causes the document's save methods to be invoked.</p>
  
  <p>From reading the documentation and other questions on Stack Overflow, it's clear that something is wrong -- I should NOT have to put this method in the NSWindowController class. I'm sure I've overlooked something silly, but for the life of me I cannot figure out what it is, or any other mention of this problem here or elsewhere on the web.</p>
  
  <p>Some additional information that may be useful -- in IB, the window's owner and delegate are set to the NSWindowController. I created a method to display the responder chain (see <a href="https://stackoverflow.com/questions/4241416/how-to-inspect-the-responder-chain">How to inspect the responder chain?</a>) and the document was not listed. Here is the output of the responder chain (however, since NSDocument is not a subclass of NSResponder, I'm not sure if it is supposed to be listed anyway).</p>
  
  <pre><code>RESPONDER CHAIN:
  &lt;NSClipView: 0x102344350&gt;
  &lt;NSScrollView: 0x102344480&gt;
  &lt;NSView: 0x102345040&gt;
  &lt;NSWindow: 0x10234e090&gt;
  </code></pre>
  
  <p>Since the saveDocument method I put into the NSWindowController class does work, that indicates to me that the window controller does know that it is associated with the document.</p>
  
  <p>So -- any thoughts as to why the document is behaving as if it is not in the responder chain?</p>
  
  <p><strong>Updated info:</strong> After setting up a new document, the initWithType method includes this temporary line to make sure that the document status is edited:</p>
  
  <pre><code>[self updateChangeCount:NSChangeDone];
  </code></pre>
  
  <p>I have verified that isDocumentEdited returns true.</p>