title: Manual modal segue does not work, View Controller is not in the window hierarchy?
body: <p>I've been searching the web and Stack Overflow for hours and I cannot resolve this issue. here's hoping you all see my mistake, because I just can't find it.</p>
  
  <p>I have a simple storyboard-based application I just started. The initial ViewController is an instance of UITabBarController with the two dummy ViewControllers from the template. Upon start up I need to check if the device is logged into an external service. If not I will show a modal ViewController that will allow the user to authenticate, if the device is authenticated then I will just show the FirstViewController.</p>
  
  <p>The following steps are everything I have done since creating the project:</p>
  
  <ol>
  <li>Create the AuthenticateViewController scene on the Storyboard</li>
  <li>Create code files for AuthenticateViewController, and assign them to the corresponding scene</li>
  <li>Create code files for a UITabBarController subclass, and associate the initial UITabBarController scene to that new subclass</li>
  <li>Create a new segue on the storyboard from the UITabBarController scene to the AuthenticateViewController scene</li>
  <li>Manually call the segue from <code>viewDidLoad</code> in the UITabBarController subclass</li>
  </ol>
  
  <p>When I run the application the modal segue does not fire, the first ViewController of the UITabBarController is shown, and I get the following output in XCode:</p>
  
  <pre><code>Warning: Attempt to present &lt;AuthenticateViewController: 0x83c0c10&gt; on &lt;EPTabBarController: 0x83be600&gt; whose view is not in the window hierarchy!
  </code></pre>
  
  <p>Relevant code below, in fact the only code I have added so far. Please let me know if screenshots or additional information would be useful. Thanks in advance for your help.</p>
  
  <p>EPTabBarController, subclass of UITabBarController:</p>
  
  <pre><code>#import "EPTabBarController.h"
  #import "AuthenticateViewController.h"
  
  @interface EPTabBarController ()
  
  @end
  
  @implementation EPTabBarController
  
  - (void)viewDidLoad
  {
      [super viewDidLoad];
  
      [self performSegueWithIdentifier:@"authenticationSegue" sender:self];
  }
  
  - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
  }
  
  @end
  </code></pre>