RadComboBox OnClientItemsRequested not firing

Is there anything about my code below that would prevent the client event "OnClientItemsRequested" from firing? I have a couple RadComboBox elements on a page that sometimes get into a state where they load nothing and don't fire the "OnClientItemsRequested" event. Is there anything I could do to FORCE this event to fire?

<telerik:RadComboBox 
  ID="SomeFilter" 
  runat="server" 
  Height="230px" Width="300px" style="margin-bottom:5px" 
  DropDownWidth="298px" 
  EmptyMessage="Choose..." 
  HighlightTemplatedItems="true" 
  EnableLoadOnDemand="true" 
  EnableVirtualScrolling="true" 
  ItemRequestTimeout="500" 
  ShowMoreResultsBox="True" 
  OnClientSelectedIndexChanging="OnClientSelectedIndexChanging"
  OnClientDropDownClosing="OnClientDropDownClosing" 
  OnClientBlur="OnClientBlur" 
  OnItemsRequested="TaskEmployeesFilter_ItemsRequested" 
  OnClientItemsRequested="OnClientItemsRequested"
  Enab开发者_StackOverflow社区leItemCaching="false">
  <ItemTemplate>
    ...
  </ItemTemplate>
</telerik:RadComboBox>

How are you binding it to data? You can invoke the event by calling the method: requestItems(), which this method makes the request from the client to the server.

See more about it here: http://www.telerik.com/help/aspnet/combobox/combo_client_model.html

Are you binding via web service, or another way?

HTH.

You might want the onClientItemsRequesting rather than onClientItemsRequested. Fires before the load on demand post back, hitting after might be killing your event.