title: EXC_BAD_ACCESS using ARC when poping back to view controller
body: <p>to begin with, here is some code:</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
  
      FirstViewController *first = [[FirstViewController alloc] init];
      SecondViewController *second = [[SecondViewController alloc] init];
      MBPullDownController *pullDownController = [[MBPullDownController alloc] initWithFrontController:first backController:second];
      [self.navigationController addChildViewController:pullDownController];
  }
  
  - (void)pushAnotherViewController:(NSNotification *)notification
  {
      AnotherViewController *another = [self.storyboard instantiateViewControllerWithIdentifier:@"anotherViewController"];
      [self pushScheduleViewController:another];
  }
  </code></pre>
  
  <p>I use the <strong>MBPullDownController</strong> open source control. Using to seperate view controllers I load into the pull down controller. This code is in a view controller called <em>RootViewController</em> which is embedded in a <em>UINavigationController</em>. Then there's a method for pushing another view controller in the navigation controller. It's when I try to use the method (in <em>AnotherViewController</em>) <code>popToRootViewController:</code> that my app crashes and the EXC_BAD_ACCESS message comes up in the console.</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>This is my code in "AnotherViewController"</p>
  
  <pre><code>- (void)popBack
  {
      RootScheduleViewController *root = [[RootScheduleViewController alloc] init];
      [self.navigationController popToViewController:root animated:YES];
  }
  </code></pre>