title: What is the difference between NSUserDefaultsController and NSArrayController?
body: <p>I have happily used a "Array Controller" object in the interface builder. The binding worked like charm and everything works like magic. </p>
  
  <p>Because of that I took a look at the "User Default Controller" - thinking that it will work similarly as the "Array Controller". To my surprise there is not binding interface in Xcode. I had to bind the UI element with the user defaults by code. Example bellow:</p>
  
  <pre><code>    [_cbPlaySound bind:@"value"
            toObject:[NSUserDefaultsController sharedUserDefaultsController]
         withKeyPath:@"values.playSound"
             options:[NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES]
              forKey:@"NSContinuouslyUpdatesValue"]];
  </code></pre>
  
  <p>Everything again works like it should. But why can't i bind the "User Default Controller" like the "Array Controller"?</p>
  
  <p>To be clear: I did red the Apple documentation, but I still don't understand why to things that seams to me that should work similarly, they don't.</p>
  
  <p>Best.</p>