title: UITextView font size not updated
body: <p>I have a <code>UITextView</code> inside a <code>UIViewController</code> which contains some buttons: two of them are used to zoom the text contained in the <code>UITextView</code>. <code>defaultFontSize</code> is initialized on <code>viewDidLoad()</code></p>
  
  <p>Those buttons have a <code>IBAction</code> linked to them...</p>
  
  <pre><code>- (IBAction)zoomIn:(id)sender {
      if(defaultFontSize &lt; 60) {
          defaultFontSize = defaultFontSize + 2;
          [theContent setFont:[UIFont systemFontOfSize:defaultFontSize]];
      }
  }
  
  /* ... */
  
  - (IBAction)zoomOut:(id)sender {
      if(defaultFontSize &gt; 14) {
          defaultFontSize = defaultFontSize - 2;
          [theContent setFont:[UIFont systemFontOfSize:defaultFontSize]];            
      }
  }
  </code></pre>
  
  <p>When I first show the <code>UIViewController</code> and tap the <code>zoomIn</code> or <code>zoomOut</code> buttons the text size in <code>theContent</code> is not changing. </p>
  
  <p>To be more precise: the methods are called (I've put some logs), but the <code>UITextView</code> font size is not updated.</p>
  
  <p>BTW it's changing if I tap other buttons (the buttond tapped are changing screen opacity, so I think that this forces a screen refresh) taking all the taps I made before (i.e. if I tapped zoomIn 2 times I got a +4 in font size) and then start works normally.</p>
  
  <p><strong>Questions:</strong>
  How can I (if possible) force whenever I want a "refresh" of the <code>UITextView</code>?
  Why my buttons are not working when I start showing the <code>UIViewController</code>, but then they work after a "screen refresh"?</p>
  
  <p>I will be glad if you can help :-)</p>