title: Binding to (Validation.Errors).CurrentItem does not work with TextBox (works with DataGrid)
body: <p>I am trying to bind ToolTip property to a (Validation.Errors).CurrentItem in code. I allready did that with DataGrid like:</p>
  
  <pre><code>var grid = new FrameworkElementFactory(typeof(Grid));
  grid.SetValue(Grid.ToolTipProperty, new Binding() {
          RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, typeof(DataGridRow), 1),
          Path = new PropertyPath("(Validation.Errors).CurrentItem.ErrorContent")
  });
  </code></pre>
  
  <p>That works, error sign appears in row header with tool tip (some error text).</p>
  
  <p>When I try to do the same with text box tool tip does not appear:</p>
  
  <pre><code>grid.SetValue(Grid.ToolTipProperty, new Binding() {
       ElementName = textBox1.Name, // tried with relative source also...
       Path = new PropertyPath("(Validation.Errors).CurrentItem.ErrorContent")
  });
  </code></pre>
  
  <p>Regards,</p>
  
  <p>Vale</p>