title: UIButton across all pages of UIPageViewController
body: <p>I am working on an iPhone app, and created a <code>UIPageViewController</code> (lets call it the <strong>container</strong>), which contains a number of <code>UIViewController</code> pages (lets call them the <strong>subpages</strong>). The <strong>subpages</strong> transition style is scroll.</p>
  
  <p>Now, what I like to do is create a button on the top right corner of the <strong>container</strong> and NOT in the <strong>subpages</strong>. The idea is, the button will stay on screen when the <strong>subpages</strong> scroll from one page to the other. If I create the button in one of the <strong>subpages</strong>, then each <strong>subpage</strong> will have its own button, and the button will scroll with the <strong>subpages</strong>. I want to keep the button without moving in the <strong>container</strong>, while the <strong>subpages</strong> scroll.</p>
  
  <p>I tried to add the button using the storyboard to the <strong>container</strong>, but it is now allowed in. I cannot drop it there, and I suspect the reason is because <strong>container</strong> is of type <code>UIPageViewController</code>.</p>
  
  <p>How can I do that using the storyboard?</p>
  
  <p>Thanks.</p>