title: Evenly space elements in StackPanel
body: <p>See this container where I have two elements. I want them to be evenly spaced, <strong>as if I were using <code>justify-content: space-between</code> (or <code>space-around</code>) in an HTML flexbox</strong>.</p>
  
  <pre class="lang-xml prettyprint-override"><code>            &lt;StackPanel Margin="10" Orientation="Horizontal"&gt;
                  &lt;ComboBox DockPanel.Dock="Left" SelectedIndex="0" Padding="6"&gt;
                      &lt;ComboBoxItem Content="Info"/&gt;
                  &lt;/ComboBox&gt;
                  &lt;Ellipse DockPanel.Dock="Right" Width="20" Height="20" Fill="Red"/&gt;
              &lt;/StackPanel&gt;
  </code></pre>
  
  <p>For this particular case, where I want them at either edge of the container, I've managed a workaround using a <code>DockPanel</code>. </p>
  
  <pre class="lang-xml prettyprint-override"><code>            &lt;DockPanel Margin="10" LastChildFill="False"&gt;
                  &lt;ComboBox DockPanel.Dock="Left" SelectedIndex="0" Padding="6"&gt;
                      &lt;ComboBoxItem Content="Info"/&gt;
                  &lt;/ComboBox&gt;
                  &lt;Ellipse DockPanel.Dock="Right" Width="20" Height="20" Fill="Red"/&gt;
              &lt;/DockPanel&gt;
  </code></pre>
  
  <p>However, this is definitely a workaround; if I had some dynamic number of elements that I wanted evenly spaced, it wouldn't work.</p>
  
  <p>Off the top of my head I imagine I could wrap each element in a <code>StackPanel</code> or other container that could stretch to share the width of its container. But is there a simpler way to set equal spacing?</p>
  
  <p>Using <code>Margin</code> or <code>Padding</code> on the individual elements is unacceptable. Unacceptable!!!!!</p>