title: How to set children Width for DockPanel to 100% inside ComboxItem?
body: <pre><code>&lt;ComboBoxItem HorizontalContentAlignment="Stretch" Width="Auto"&gt;
       &lt;DockPanel Background="Red" HorizontalAlignment="Stretch" LastChildFill="True" Width="Auto"&gt;
          &lt;Label DockPanel.Dock="Left" Name="lbName" &gt;&lt;/Label&gt;
          &lt;Image DockPanel.Dock="Right" HorizontalAlignment="Right" Name="image" Source="/Test;component/Images/cross.jpg" Width="16" Height="16" Stretch="UniformToFill" /&gt;
          &lt;Image DockPanel.Dock="Right" HorizontalAlignment="Right" Name="image2" Source="/Test;component/Images/cross.jpg" Width="16" Height="16" Stretch="UniformToFill" /&gt;
      &lt;/DockPanel&gt;
  &lt;/ComboBoxItem&gt;
  </code></pre>
  
  <p>Like you can see on image below <code>DockPanel</code>(marked red) doesn't take 100% width of <code>ComboboxItem</code>.</p>
  
  <p>How to stretch <code>DockPanel</code> to size of <code>ComboboxItem</code> in XAML?</p>
  
  <p><img src="https://i.stack.imgur.com/Q4Nqn.png" alt="enter image description here"></p>