title: Visibility Collapsed leaving a slight space in the UI
body: <p>Given the following xaml structure</p>
  
  <pre><code>&lt;Grid&gt;
      &lt;StackPanel&gt;
        &lt;TextBlock&gt;
             &lt;TextBlock&gt;Block 1&lt;/TextBlock&gt;
             &lt;TextBlock&gt;Block 2&lt;/TextBlock&gt;
           &lt;/TextBlock&gt;
        &lt;TextBlock&gt;
             &lt;TextBlock Visibility="Collapsed"&gt;Block 3&lt;/TextBlock&gt;
             &lt;TextBlock&gt;Block 4&lt;/TextBlock&gt;
        &lt;/TextBlock&gt;
        &lt;TextBlock&gt;
             &lt;TextBlock&gt;Block 5&lt;/TextBlock&gt;
             &lt;TextBlock&gt;Block 6&lt;/TextBlock&gt;
           &lt;/TextBlock&gt;
      &lt;/StackPanel&gt;
    &lt;/Grid&gt;
  </code></pre>
  
  <p>I expect this output:</p>
  
  <pre><code>Block 1 Block 2 
  Block 4 
  Block 5 Block 6
  </code></pre>
  
  <p>But I get this</p>
  
  <pre><code>Block 1 Block 2 
   Block 4   
  Block 5 Block 6
  </code></pre>
  
  <p>Where is the space before <code>Block 4</code> coming from, and how do I make it go away?</p>