title: Unable to select item in spark.components.List after de-selection
body: <p>I have a spark List defined as:</p>
  
  <pre><code>&lt;s:List id="symbolList"  dataProvider="{symbolListCollection}" change="symbolNameChangeHandler(event)"&gt;&lt;/s:List&gt;
  </code></pre>
  
  <p>With the change handler defined like this:</p>
  
  <pre><code>protected function symbolNameChangeHandler(event:IndexChangeEvent):void {
     symbolList.validateProperties();
     changeSymbolView(symbolList.selectedItem);
  }
  </code></pre>
  
  <p>and symbolListCollection as an ArrayList filled with Strings.</p>
  
  <p>At first, the change event works fine, and I get what I expect.</p>
  
  <p>However, if I Ctrl-click on the selected item, to de-select it, i am unable to ever select an item again.</p>
  
  <p>When I click on something to try to select it, the change event DOES fire, however, the ItemChangeEvent has both oldIndex and newIndex set to -1</p>
  
  <p>Any idea what I might have done to cause this, or what I can do to remedy it?</p>