title: Show Tooltip when text is being trimmed
body: <pre><code>  &lt;TextBlock Width="100" Text="The quick brown fox jumps over the lazy dog" TextTrimming="WordEllipsis"&gt;
       &lt;TextBlock.ToolTip&gt;
          &lt;ToolTip DataContext="{Binding Path=PlacementTarget, RelativeSource={x:Static RelativeSource.Self}}"&gt;
             &lt;TextBlock Text="{Binding Text}"/&gt;
          &lt;/ToolTip&gt;
       &lt;/TextBlock.ToolTip&gt;
    &lt;/TextBlock&gt;
  </code></pre>
  
  <p>How can I show the <code>ToolTip</code> only when the text is trimmed?  Like the windows desktp shortcut icons.</p>