title: DataGridTextColumn.IsReadOnly seems to be faulty
body: <p>If I create a binding to the <code>IsReadOnly</code> property of the <code>DataGridTextColumn</code>, it does not actualize. If I set it through markup, it works.</p>
  <pre class="lang-xml prettyprint-override"><code>&lt;DataGridTextColumn IsReadOnly=&quot;{Binding IsReferenceInactive}&quot;/&gt; &lt;!-- NOP --&gt; 
  
  &lt;DataGridTextColumn IsReadOnly=&quot;True&quot;/&gt; &lt;!-- Works as expected, cell is r/o --&gt;
  </code></pre>
  <p>The <code>IsReferenceInactive</code> property is a DP and works fine (For testing purposes I've bound it to a checkbox, that worked)</p>
  <p>Is this a known limitation?</p>
  <p><strong>Update</strong></p>
  <p>Uups,  other than I wrote, there is a message in the output window:</p>
  <blockquote>
  <p>System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=IsReferenceInactive; DataItem=null; target element is 'DataGridTextColumn' (HashCode=23836176); target property is 'IsReadOnly' (type 'Boolean')</p>
  </blockquote>