title: WPF ComboBox TextSearch using Contains instead of StartsWith
body: <p>I got a <code>ComboBox</code> with alot of "Customers" using  <code>MultiBinding</code> as <code>Text</code> (for instance "644 Pizza Place") and this works great searching from start (CustomerNumber). But how do I make it match and select by just enter "Pizza Place"?</p>
  
  <pre><code>&lt;MultiBinding StringFormat="{}{0} {1}"&gt;
      &lt;Binding Path="CustomerNumber" /&gt;
      &lt;Binding Path="CustomerName" /&gt;
  &lt;/MultiBinding&gt;
  </code></pre>