title: How to bind an element to a property which belongs to the root element of a control?
body: <p>
  The question may sound a little confusing, but the problem I'm currently facing is this:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;Button x:Class="sandbox.BtnLabel"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
          xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
          x:Name="this"&gt;
      &lt;Button.ToolTip&gt;
          &lt;TextBlock Background="Yellow" Text="{Binding ElementName=this, Path=LabelText}"/&gt;
      &lt;/Button.ToolTip&gt;
      &lt;TextBlock Background="Yellow" Text="{Binding ElementName=this, Path=LabelText}"/&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p>Only the second binding works, which sets the content of the button. The first one, which I would like to use to set the contents of the tooltip of the button (via the LabelText dependency property) does not work.</p>
  
  <p>Is it possible to make the first binding work?
  Thanks.</p>