title: Binding datagrid column width
body: <p>I have two datagrids with one column each.
  First:</p>
  
  <pre><code>&lt;DataGrid.Columns&gt;
     &lt;DataGridTextColumn x:Name="FilterTextCol01" 
                         IsReadOnly="False" 
                         Width="{Binding ElementName=TextCol01, Path=ActualWidth, Mode=TwoWay}" /&gt;
  &lt;/DataGrid.Columns&gt;
  </code></pre>
  
  <p>Second:</p>
  
  <pre><code>&lt;DataGridTextColumn CellStyle="{StaticResource DataGridColumnContentLeft}"
                      local:DataGridUtil.Name="TextCol01"
                      x:Name="TextCol01"
                      Header="TextCol01"
                      SortMemberPath="TextCol01"
                      Binding="{Binding TextCol01}" 
                      Width="Auto" 
                      IsReadOnly="True"/&gt;
  </code></pre>
  
  <p>Binding of the width of first column to the width of the second doesn't work.
  If I'm doing it in code that way:</p>
  
  <pre><code>FilterTextCol01.Width = TextCol01.ActualWidth;
  </code></pre>
  
  <p>It works. 
  Could anyone tell me why the first approach doesn't work?</p>