title: RelativeLayout.HeightConstraint doesnt fill my RelativeLayout
body: <p>I am using a ListView Header, and i want to fill a photo which it will take place in 1/3  of screen size so inside my ListView Header i have set this code below:</p>
  
  <pre><code>&lt;ListView.Header &gt;
               &lt;RelativeLayout BackgroundColor="Red"&gt;
                  &lt;StackLayout
                    BackgroundColor="Gainsboro"
                    RelativeLayout.WidthConstraint ="{ConstraintExpression
                    Type=RelativeToParent,
                    Property=Width,
                    Factor=1}"
                    RelativeLayout.HeightConstraint ="{ConstraintExpression
                    Type=RelativeToParent,
                    Property=Height,
                    Factor=0.3}"/&gt;
              &lt;/RelativeLayout&gt;
          &lt;/ListView.Header&gt;
  </code></pre>
  
  <p>Here is my result</p>
  
  <p><a href="https://i.stack.imgur.com/yXOpF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yXOpF.png" alt="enter image description here"></a></p>
  
  <p>How can i fix to match stackLayout inside relativelayout?</p>