title: TextBox ScrollBar Not Showing After Customization
body: <p>I designed my custom WPF TextBox as follows.</p>
  
  <pre><code>&lt;TextBox VerticalAlignment="Bottom" Name="txtResult" Padding="8" FontFamily="Consolas" Margin="5" TextWrapping="Wrap"&gt;
                  &lt;TextBox.Template&gt;
                      &lt;ControlTemplate TargetType="{x:Type TextBox}"&gt;
                          &lt;Grid&gt;
                              &lt;TextBox Margin="4" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Text}" BorderThickness="0" Background="{x:Null}" SnapsToDevicePixels="True"  ScrollViewer.VerticalScrollBarVisibility="Visible"/&gt;
                              &lt;Rectangle  Stroke="{StaticResource ResourceKey=detailMarkBrush}" StrokeThickness="0"/&gt;
                          &lt;/Grid&gt;
                      &lt;/ControlTemplate&gt;
                  &lt;/TextBox.Template&gt;
              &lt;/TextBox&gt;
  </code></pre>
  
  <p>But even after adding the <code>ScrollViewer.VerticalScrollBarVisibility="Visible"</code> or wrapping the TextBox in <code>ScrollViewer</code>, my scrollbars don't show. 
  Any suggestions?</p>
  
  <p>Thanks.</p>