title: How to make the entire page scrollable, when UITextView is inside UIScrollView?
body: <p>Currently, I have a layout design as following</p>
  <pre><code>[Safe Area]
  
      [Scroll View (In green color)]
          
          [Custom View (In red color)]
              
              [Horizontal Stack View]
                  [Button 1]
                  [Button 2]
              
              [Text View]
  
      [Bottom Toolbar]
  </code></pre>
  <p>It is designed so that, as the content of <code>[Text View]</code> grow, user can scroll vertically <code>[Text View]</code> together  with the buttons group (<code>[Horizontal Stack View]</code>)</p>
  <p>It suppose to look as the following</p>
  <p><a href="https://i.stack.imgur.com/wOtfD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wOtfD.png" alt="enter image description here" /></a></p>
  <p>We think we have used the correct constraints, between <code>[Custom View]</code> and <code>[Scroll View]</code></p>
  <pre><code>Custom View.top = Content Layout Guide.top
  Custom View.trailing = Content Layout Guide.trailing
  Custom View.leading = Content Layout Guide.leading
  Custom View.bottom = Content Layout Guide.bottom
  Custom View.width = Frame Layout Guide.width
  </code></pre>
  <p>One warning we are getting from Xcode is</p>
  <pre><code>Scrollable content size is ambiguous for &quot;Scroll View&quot;.
  </code></pre>
  <p>Hence, to avoid such, we need to add</p>
  <pre><code>Custom View.centerX = Frame Layout Guide.centerX
  Custom View.centerY = Frame Layout Guide.centerY
  </code></pre>
  <p>However, when we execute the app, only <code>[Text View]</code> is vertically scrollable, when the text content grows. <strong>The top buttons group remains static.</strong></p>
  <p>We try to disable scrolling behaviour in <code>[Text View]</code> itself. Again, the entire page is not scrollable, when the text content grows.</p>
  <p>Do you have any idea how to fix this, so that when text content grow, <strong>the top button group can scroll together with text view?</strong></p>
  <p>The demo is located at <a href="https://github.com/yccheok/ios-tutorial/tree/learn-scroll-view/NavigationController" rel="nofollow noreferrer">https://github.com/yccheok/ios-tutorial/tree/learn-scroll-view/NavigationController</a></p>