title: Why does navigationItem.titleView align left when presentmodalviewcontroller called?
body: <p>I'm using a UILabel for the titleView of a navigation bar (I'm making simple in-app web browser).  It works fine, except that when I present a modal view controller, the titleView shifts from the center of the navbar to the far left (underneath the back button).  I've tested in 3.0 and up.  Here is relevant code:</p>
  
  <pre><code>- (void)viewDidLoad {
      [super viewDidLoad];
      // Title view label
      CGRect labelFrame = CGRectMake(0.0, 0.0, 120.0, 36.0); 
      UILabel *label = [[[UILabel alloc] initWithFrame:labelFrame] autorelease];
      label.font = [UIFont boldSystemFontOfSize:14];
      label.numberOfLines = 2;
      label.backgroundColor = [UIColor clearColor];
      label.textAlignment = UITextAlignmentCenter;
      label.textColor = [UIColor whiteColor];
      label.shadowColor = [UIColor blackColor];
      label.shadowOffset = CGSizeMake(0.0, -1.0);
      label.lineBreakMode = UILineBreakModeMiddleTruncation;
      self.navigationItem.titleView = label;
  }
  
  -(void)displayComposerSheet:(NSString*)mailto 
  {
      MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
      picker.mailComposeDelegate = self;
      [self presentModalViewController:picker animated:YES];
      [picker release];
  }
  </code></pre>
  
  <p>Screenshots: 
  <img src="https://i.stack.imgur.com/p80VQ.jpg" alt="enter image description here"></p>
  
  <p>Any idea why this is happening? Thanks.</p>