title: How to make WPF Combobox's Dropdown stays open & Placement
body: <p>I want to have the Combobox editable and with the dropdown stays open. </p>
  
  <p>At the moment with these properties been set:</p>
  
  <pre><code>IsEditable="True" IsDropDownOpen="True" StaysOpenOnEdit="True" 
  </code></pre>
  
  <p>Whenever the user click on the input textbox or the focus is changed to other controls, the dorpdown closes. So I updated the template (the one included in <a href="http://wpf.codeplex.com/wikipage?title=WPF%20Themes" rel="noreferrer">WPF Theme</a>: BureauBlue) to have the <code>Popup</code> <code>IsOpen="true"</code> in this particular case that makes the dropdown stays open, but now when user drag&amp;move the window's position, the dropdown will <strong>not</strong> update its position automatically and <strong>stay</strong> in the old position. </p>
  
  <p><strong>How can I make it automatically update its position while it is open</strong>?</p>