title: NSInvalidArgumentException in master-detail format
body: <p>I have an issue when I use Master-Detail format.</p>
  
  <p>I set the following code in AppDelegate.m</p>
  
  <pre><code>FileContent1 *bug4 = [[FileContent1 alloc] initWithTitle:@"Lady Bug" 
      url1:@"file:///Users/daemonwolf/Desktop/11.htm" 
      rating:1 
      thumbImage:[UIImage imageNamed:@"ladybugThumb.jpg"] 
      fullImage:[UIImage imageNamed:@"ladybug.jpg"]];
  
  NSMutableArray *bugs = [NSMutableArray arrayWithObjects:bug1, bug2, bug3, bug4, nil];
  
  UINavigationController * navController = (UINavigationController *) self.window.rootViewController;
  MasterViewController * masterController = [navController.viewControllers objectAtIndex:0];
  masterController.bugs = bugs;
  </code></pre>
  
  <p>In MasterViewController.h, I set:</p>
  
  <pre><code>@property (strong) NSMutableArray *bugs;
  </code></pre>
  
  <p>and in MasterViewController.m:</p>
  
  <pre><code>@implementation MasterViewController
  @synthesize bugs = _bugs;
  </code></pre>
  
  <p>But when I debug it, I get following exception:</p>
  
  <blockquote>
    <p>[UINavigationController setBugs:]: unrecognized selector sent to
    instance 0x7179250 2013-06-20 23:38:01.406 EBS[4682:11303] <em>*</em>
    Terminating app due to uncaught exception
    'NSInvalidArgumentException', reason: '-[UINavigationController
    setBugs:]: unrecognized selector sent to instance 0x7179250'</p>
  </blockquote>
  
  <p>Why does this happen?</p>