title: wpf textblock autosize/layout in stackpanel
body: <p>I have the following stack panel</p>
  
  <pre><code>&lt;StackPanel&gt;
                  &lt;TextBlock Text="{Binding AddressLine1}" /&gt;
                  &lt;TextBlock Text="{Binding AddressLine2}" /&gt;
                  &lt;TextBlock Text="{Binding AddressLine3}"  /&gt;
                  &lt;TextBlock Text="{Binding AddressLine4}"  /&gt;
  &lt;/StackPanel&gt;
  </code></pre>
  
  <p>and my AddressLine2 string is null on the bound object.</p>
  
  <p>My stack panel renders like</p>
  
  <pre><code>| AddressLine1 |
  |              |
  | AddressLine3 |
  | AddressLine4 |
  </code></pre>
  
  <p>but I want it to render like </p>
  
  <pre><code>| AddressLine1 |
  | AddressLine3 |
  | AddressLine4 |
  </code></pre>
  
  <p>is this possible, or am I missing an obvious way to do it?</p>
  
  <p>Thanks, 
  Chris</p>