title: How can I prevent a dropdown from closing when I`ve selected an item?
body: <p>I have custom control, derived from combobox. </p>
  
  <p>I want it to not close itself when I select an item. If I set the <code>IsDropDownOpen</code> property to false in <code>protected override void OnDropDownClosed(EventArgs e)</code>, this method just starts to chain invoke itself. </p>
  
  <p>If <code>IsDropDownOpen</code> is set in the <code>OnSelectionChanged</code> handler nothing happens. </p>
  
  <p>Any suggestions?</p>