title: IsMouseOver trigger for DockPanel not firing unless children are hovered over
body: <p>This question has been asked a couple of times before, but at this time, none of the answers I've found turned out to be working.</p>
  
  <p>So I have a custom <code>DockPanel</code> with 2 child elements inside, 1 <code>TextBox</code> and 1 <code>Image</code>. 
  I intended to have the DockPanel change color on hover, so I put a Trigger inside of it. But currently, it only changes color if I hover over the children, whereas a hover over whitespace between elements doesn't do anything. </p>
  
  <p>I've read similar posts which mentioned using <code>isHitTestVisible</code>, but it doesn't do anything.</p>
  
  <p>Short version of my code is the following:</p>
  
  <pre><code>&lt;DockPanel&gt;
  
      &lt;!-- Change color on mouse hover --&gt;
      &lt;DockPanel.Style&gt;
          &lt;Style&gt;
              &lt;Style.Triggers&gt;
                   &lt;Trigger Property="DockPanel.IsMouseOver" Value="True"&gt;
                         &lt;Setter Property="DockPanel.Background" Value="#FFe6ffe6"/&gt;
                   &lt;/Trigger&gt;
              &lt;/Style.Triggers&gt;
          &lt;/Style&gt;
      &lt;/DockPanel.Style&gt;
  
      &lt;StackPanel Orientation="Vertical" DockPanel.Dock="Center"&gt;
          &lt;!-- TextBox and Image code here --&gt;
      &lt;/StackPanel&gt;
  &lt;/DockPanel&gt;
  </code></pre>