title: Navigation Controller not work after using Present model controller
body: <p>I have an view with 3 buttons in that whenver user clicked on 1st button click it goes to seconViewController
  Used this code.</p>
  
  <pre><code>PerformViewController * pvc=[[PerformViewController alloc]initWithNibName:@"PerformViewController" bundle:nil];
  
  [self presentViewController:pvc animated:YES completion:nil];
  [self dismissViewControllerAnimated:YES completion:nil];
  </code></pre>
  
  <p>and another two  buttons i used the  <code>[self.navigationController pushViewController:gmavc animated:YES];</code>
   it works fine but when used tapped on 1st button clicked present the secondViewController.
  and whne back to it's viw controller i used this code</p>
  
  <pre><code>ViewController *vc=[[ViewController alloc]initWithNibName:@"ViewController" bundle:nil];
  
  [self presentViewController:vc animated:YES completion:nil];
  
  [self dismissViewControllerAnimated:YES completion:nil];
  </code></pre>
  
  <p>After back to parant view controller my another two button push navigation controller not working not why this happening.</p>