title: horizontalalingment in textblock don't work
body: <p>I have code like this in xaml:</p>
  
  <pre><code>                    &lt;ListBoxItem&gt;
                          &lt;StackPanel Orientation="Horizontal"&gt;
                              &lt;TextBlock Text="{DynamicResource Referee}" Width="120" FontWeight="Bold" Margin="0 0 5 0" HorizontalAlignment="Right"&gt;&lt;/TextBlock&gt;
                              &lt;TextBlock Text="LOL" Margin="0 0 5 0"&gt;&lt;/TextBlock&gt;
                          &lt;/StackPanel&gt;
                      &lt;/ListBoxItem&gt;
  </code></pre>
  
  <p>The problem is fact that first textBlock is not aligned to right but still to left.</p>
  
  <p>There are many listbox items and i want to have align first column to right and second column to left. In each stackPanel first textblock has width 120. ListBox is in grid column which column width is set to Auto.</p>
  
  <p>How can I solve that problem?</p>