title: iOS removing an object from superview demolishes auto layout and disables scrollview
body: <p>I have a button that's programmatically laid out and positioned with manually set constraints. I then try to remove the button from the view by calling <code>removeFromSuperview</code>. Removing the button causes a collection view subview positioned below the button to lose it's position in the <code>scrollview</code> and align itself to the top of the <code>superview</code> behind all the other objects. I expected the collection view to simply move up to where the button was once the button and it's constraints had been removed from the view. <strong>What am I missing?</strong></p>
  
  <p><strong>Button creation:</strong></p>
  
  <pre><code>aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  [aButton addTarget:self
              action:@selector(buttonPressed:)
    forControlEvents:UIControlEventTouchUpInside];
  [aButton setTitle:@"Expand" forState:UIControlStateNormal];
  [aButton setTranslatesAutoresizingMaskIntoConstraints:NO];
  [self addSubview:aButton];
  </code></pre>
  
  <p><strong>Button removal:</strong></p>
  
  <pre><code>- (void)buttonPressed:(UIButton *)sender{
      NSLog(@"Pressed");
      [aButton removeFromSuperview];
  }
  </code></pre>
  
  <p><strong>Vertical positioning (detailOfLocation is the collection view):</strong></p>
  
  <pre><code>[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[locationImageContainer(213)][locationTitle][locationDescription][aButton][detailOfLocation]|"
                                                                       options:0
                                                                       metrics:0
                                                                         views:viewArranging]];
  </code></pre>
  
  <p><strong>[Edit]</strong></p>
  
  <p>The removal of the button also seems to disable the scrolling ability of the UIScrollView that is the superview where everything is placed.</p>