title: Binding to ActualWidth does not work
body: <p>In a Silverlight 3.0 application I'm attempting to create a rectangle in a canvas and have it stretch the whole width of the canvas.  I have attempted to do this by binding to the <code>ActualWidth</code> property of a parent container (seem sample below), however while I don't see any binding errors the value is not being bound.  The rectangle is not visible as its width is zero.  In addition tried binding to the <code>ActualWidth</code> of the canvas that contains my rectangle but this made no difference.</p>
  
  <p>I did <a href="https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=425334" rel="noreferrer">find this bug logged on Microsoft Connect</a> but there were no workarounds listed.</p>
  
  <p>Has anyone been able to solve this issue or can they point to solution?</p>
  
  <p>Edit: The original code sample was not accurate of what I'm trying to achieve, updated for more clarity.</p>
  
  <pre><code>&lt;UserControl&gt;
      &lt;Border BorderBrush="White"
              BorderThickness="1"
              CornerRadius="4"
              HorizontalAlignment="Center"&gt;
          &lt;Grid x:Name="GridContainer"&gt;
              &lt;Rectangle Fill="Aqua"
                         Width="150"
                         Height="400" /&gt;
              &lt;Canvas&gt;
                  &lt;Rectangle Width="{Binding Path=ActualWidth, ElementName=GridContainer}"
                             Height="30"
                             Fill="Red" /&gt;
              &lt;/Canvas&gt;
  
              &lt;StackPanel&gt;
                  &lt;!-- other elements here --&gt;
              &lt;/StackPanel&gt;
          &lt;/Grid&gt;
      &lt;/Border&gt;
  &lt;/UserControl&gt;
  </code></pre>