title: Color of view which is a subView of scrollView is not appearing when I am usign auto layout?
body: <p>I am adding <code>scrollView</code> using constraints and it is working right. But it is showing strange behaviour. </p>
  
  <p><strong>When I am adding frame of <code>scrollView</code> as <code>[SBV setFrame:CGRectMake(0, 0, scrllView.frame.size.width,1000)];</code> then its color is <code>clearColor</code> always no matter what I am givig to it</strong>.</p>
  
  <p><strong>Code:</strong></p>
  
  <pre><code>UIScrollView *scrllView=[UIScrollView new];
  [scrllView setTranslatesAutoresizingMaskIntoConstraints:NO];
  
  [self.view addSubview:scrllView];
  [self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrllView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1.0 constant:0]];
  
  [self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrllView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.0 constant:0]];
  
  
  [self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrllView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0 constant:0]];
  
  [self.view addConstraint:[NSLayoutConstraint constraintWithItem:scrllView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeBottom multiplier:1 constant:0]];
  
  
  [scrllView setContentSize:CGSizeMake(self.view.frame.size.width, 1000)];
  
  
  UIView *SBV=[UIView new];
  [SBV setTranslatesAutoresizingMaskIntoConstraints:YES];
  
  [SBV setFrame:CGRectMake(0, 0, scrllView.frame.size.width,1000)];
  [SBV setBackgroundColor:[UIColor grayColor]];
  
  [scrllView addSubview:SBV];
  </code></pre>
  
  <p><strong>When I am adding frame of <code>view</code> as <code>[SBV setFrame:CGRectMake(0, 0,self.view.frame.size.width,1000)];</code> then its color is same as given my me. Gray in this case</strong></p>