title: Silverlight 4 toolkit, charting and lineSeries is null
body: <p>I create a Silverlight Chart, with the Silverlight 4 toolkit, the April release.</p>
  
  <p>Consider the following chart:</p>
  
  <pre><code> &lt;Grid x:Name="LayoutRoot" Background="White"&gt;
    &lt;Charting:Chart Title="Chart to test" Name="MySuperChart"&gt;
     &lt;Charting:LineSeries x:Name="MyLineSeries" Title="Something" /&gt;
    &lt;/Charting:Chart&gt;
   &lt;/Grid&gt;
  </code></pre>
  
  <p>So far so good. I can access the Series in the chart by <code>MySuperChart.Series[0]</code> But when I try to reference MyLineSeries, it appears to be null.
  <a href="https://i.stack.imgur.com/OJwDt.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OJwDt.jpg" alt="picture"></a>
  
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