title: UIBlurEffect not blurring on device but works in simulator
body: <p>I'm trying to make a <code>UIView</code> with a <code>UIVisualEffectView</code> subview with a <code>UIBlurEffect</code> as the effect. The view is created off the side of the screen and then is slid in using an animation. </p>
  
  <p>Everything works just fine on the simulator (I've tested on an iPhone 4S and an iPhone 6) however on my phone (iPhone 6) the blur just isn't blurring, it looks more like a dark grey with an <code>alpha</code> of 0.5. In addition, when I take a screenshot of the device or open it up from the home screen, the blur is rendered for that single frame before consistent rendering starts again.</p>
  
  <p>Here's a screenshot of the view as it is at the moment:
  <img src="https://i.stack.imgur.com/TLPFr.png" alt="enter image description here"></p>
  
  <p>However on the device the blur isn't there, it's essentially just a dark, transparent view.</p>
  
  <p>Here's the code I use to initialise the view, the <code>blurView</code> and <code>vibrancyView</code> properties are declared as global variables:</p>
  
  <pre><code>init(left: Bool){
      self.left = left
      let screenSize = UIScreen.mainScreen().bounds.size
  
      var rect: CGRect
      if left{
          rect = CGRectMake(-screenSize.width*0.3, 0, screenSize.width*0.3, screenSize.height)
      }else{
          rect = CGRectMake(screenSize.width, 0, screenSize.width*0.3, screenSize.height)
      }
  
      super.init(frame: rect)
      let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
      blurView = UIVisualEffectView(effect: blurEffect)
      blurView.frame = CGRectMake(0, 0, self.frame.width, self.frame.height)
      self.addSubview(blurView)
      let vibrancy = UIVibrancyEffect(forBlurEffect: blurEffect)
      vibrancyView = UIVisualEffectView(effect: vibrancy)
      vibrancyView.frame = blurView.frame
      blurView.addSubview(vibrancyView)
  
      self.userInteractionEnabled = true
  }
  </code></pre>
  
  <p>And to move the superView, that contains the blurView, in:</p>
  
  <pre><code>func moveIn(){
      UIView.animateWithDuration(0.3, animations: { () -&gt; Void in
          var center = self.center
          if self.left{
              center.x = UIScreen.mainScreen().bounds.size.width*0.15
          }else{
              center.x = UIScreen.mainScreen().bounds.size.width*0.85
          }
          self.center = center
      })
  }
  </code></pre>
  
  <p>As I said before the animation and such works fine but the blurView doesn't blur.</p>
  
  <p>I'm not sure what's going on with this, it makes me think it's something to do with rendering frames but I'm no guru so if anyone has any ideas I'd be more than grateful.</p>