title: Why tintColor doesn't work on navigation bar or toolbar on iOS7
body: <p>On iOS7 of iPad, first, I setup an modal view controller, the size is 320 * 460, then, in this modal view controller, I presented another navigation view controller, after this, the tint color of navigation bar and tool bar of the presented navigation controller turns gray. I have tried to set tint color of navigation bar and tool bar, but it just doesn't work.</p>
  
  <p>Then I tried to present the navigation controller directly, then all tint color works both on navigation bar and tool bar.</p>
  
  <p>I have tried with the <code>barTintColor</code> property of navigation bar and tool bar, it works.</p>
  
  <p>I don't know what happens.</p>
  
  <p><strong>Update</strong></p>
  
  <p>first, I define a view controller: modalViewController
  The present the modal view controller like this:</p>
  
  <pre><code>if (DeviceIsPad()) // DeviceIsPad is a method defined somewhere to tell that the device is an iPad.
      modaViewController.modalPresentationStyle = UIModalPresentationFormSheet;
  
  //here self is a normal view controller
  [self presentViewController:modalViewController animated:YES completion:NULL];
  </code></pre>
  
  <p>Second, define a navigation view controller: navigationController
  Present the navigation controller like this:</p>
  
  <pre><code>if (DeviceIsPad())
      navigationController.modalPresentationStyle = UIModalPresentationCurrentContext;
  
  // here self means the modalViewController mentioned above
  [self presentViewController:navigationController animated:YES completion:nil];
  </code></pre>
  
  <p>I setup the navigation bar and toolbar bar items in 'viewDidLoad' method of navigationController. </p>
  
  <p>By default, when the navigation view controller comes out, all toolbar button items(The items are built with just basic title like <code>Cancel</code>, <code>OK</code>) turns to be gray.</p>
  
  <p>At the same time, I have tried to set <code>tintColor</code> of <code>tool bar</code> and <code>navigation bar</code>. Both instance method and appearance method(like <code>[[UIToolBar appearance] setTintColor:[UIColor blueColor]]</code>) are used. But it still doesn't work.                                                                   </p>
  
  <p>And then I tried to present the <code>navigationViewController</code> mentioned above with <code>UIModalPresentationFormSheet</code> style directly from a normal view controller, then all tintColor for navigation bar and tool bar turns to be the blue color(the system blue color). </p>