ADBannerView shows up as white
<p>I am trying to implement a shared <code>ADBannerView</code>, which is kept in the App Delegate.</p>

<p>Is there any specific reason why the first time the banner loads in a View Controller it shows up as white?</p>

<p>Then in the following loads for that View Controller, the light-blue iAd banner gets loaded correctly.</p>