title: UINavigationController is not always pushing an item?
body: <p><img src="https://i.stack.imgur.com/JTh95.png" alt="navigation bar"></p>
  
  <p>I pushing view form my first view to second view. When second view appear then navigation bar seem like above image. In this image  i have a button which title is "List". When i click on list button then appear third view. for that i have used this code...</p>
  
  <pre><code> -(IBAction)list{
  place_Object=[[Places alloc] initWithNibName:@"Places" bundle:nil];
  
  [self.navigationController pushViewController:place_Object animated:YES];
  [place_Object release];
  //self.navigationItem.backBarButtonItem = [[[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStyleBordered target:nil action:nil] autorelease];
  </code></pre>
  
  <p>}</p>
  
  <p>Now problem is when click on list button then sometime view appear and sometime view not push by navigation and giving any error. What is error in this code or what is mistake so that it occur.</p>
  
  <p>Thanks in advance...</p>