title: XamarinForms: StackLayout inside RelativeLayout is not filling the whole screen
body: <p>I have this:</p>
  
  <pre><code>&lt;RelativeLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BackgroundColor="Red"&gt;
                  &lt;StackLayout Orientation="Vertical" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" Padding="0,15" Spacing="10"&gt;&lt;/StackLayout&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>But for some reason, even tough the RelativeLayout clearly expands, the StackLayout doesn't. How can I get the StackLayout to stretch horizontally and fill the whole width/height of the screen?</p>