title: Xcode warning: "This will cause the effect to appear broken until opacity returns to 1"
body: <p>I have a prototype cell and I put a <code>UIVisualEffectView</code> inside its <code>ContentView</code>. Visual Effect View's Blur Style is Dark and Vibrancy is off. Then I set the alpha of the Visual Effect View to 0,5 using the IB. </p>
  
  <p>Then on runtime, I get a warning that says: </p>
  
  <pre><code>&lt;UIVisualEffectView ...&gt; is being asked to animate its opacity. This will cause the effect to appear broken until opacity returns to 1.
  </code></pre>
  
  <p>I couldn't understand why this warning is there and how I can set this alpha property properly.</p>