title: Xamarin Forms On Platform The property 'Default' is set more than once
body: <p>I am using Xamarin.Forms version 3.2.0.809874-pre3.</p>
  <p>I am facing a problem that with this version I am getting the error &quot;The property 'Default' is set more than once&quot; when using OnPlatform at XAML.</p>
  <p>Here is my code:</p>
  <pre><code>&lt;ContentPage.Padding&gt;
      &lt;OnPlatform x:TypeArguments=&quot;Thickness&quot;&gt;
          &lt;On Platform=&quot;Android&quot;&gt;10,5,10,0&lt;/On&gt;
          &lt;On Platform=&quot;iOS&quot;&gt;10,20,10,0&lt;/On&gt;
      &lt;/OnPlatform&gt;
  &lt;/ContentPage.Padding&gt;
  </code></pre>