title: ViewController is leaving 20px white from lower part of screen when pushed
body: <p>I am using multiple controller during launch of an application in app delegate. One controller is for registration and the second controller is tabbar. tabbar was loading fine but when I pushed registration controller on window, contents went up by 20 units and I have good white blank screen at bottom. Therefore I recreated frame of my registration view controller in its viewdidload method and slided it 20 units down. The code is </p>
  
  <pre><code>self.view.frame = CGRectMake(0, 20, self.view.frame.size.width, self.view.frame.size.height);
  </code></pre>
  
  <p>and code in my app delegate for launch application was </p>
  
  <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
  
      if (![self accountExists]) {
                  //code if account does not exists on iphone app database
          self.registerAccount = [[registerViewController alloc] initWithNibName:@"registerViewController" bundle:nil];
          [window addSubview:registerAccount.view];
      }
      else if([self autoLoginForAnyAccount]){
          //code for autologin to app
      }
      else {
          self.tabBarController.selectedIndex = 1;
          self.tabBarController.delegate = self;
          [window addSubview:tabBarController.view];
      }
      [window makeKeyAndVisible];
      return YES;
  }
  </code></pre>
  
  <p>if anyone knows why there is a white space at bottom when registration controller is pushed then please share it with me.</p>