title: dojo.data.ItemFileReadStore: Invalid item argument with Dijit combobox
body: <p>I have a jsp page with a dijit.form.ComboBox which is populated by a dojo.data.ItemFileReadStore connecting to a back end java server.  It works almost as expected, the combobox shows the results correectly.  Problem is that I receive a 'dojo.data.ItemFileReadStore: Invalid item argument.' when scrolling in a results list with the keyboard arrow keys.  Selecting with the mouse however works fine.</p>
  
  <p>Dojo version is 1.2.3</p>
  
  <p>This is how I've put it in place on my jsp:</p>
  
  <pre><code>&lt;input type="text" id="value"
  dojoType="dijit.form.ComboBox"
  autoComplete="false"
  searchAttr="name"
  forceValidOption="true"
  hasDownArrow="false"
  onKeyUp="populateValue"
  /&gt;
  
  &lt;script type="text/javascript"&gt;
  function populateValue() {
      valueWidget = dijit.byId("value");
      var selectedValue = valueWidget.getValue();
      var url = "${contextPath}/someUrl?selectedValue=" + selectedValue + "%";
      store = new dojo.data.ItemFileReadStore({url:url});
      valueWidget.store = store;
      return;
      }
  &lt;/script&gt;
  </code></pre>
  
  <p>Here is the JSON I receive from the server:</p>
  
  <pre><code>{"items":[
      {"name":"My string 1","label":"My string 1"},
      {"name":"My string 2","label":"My string 2"},
      {"name":"Mev.","label":"Mev."}],
  "identifier":"name"}
  </code></pre>
  
  <p>Any idea what's going wrong here?</p>