Wicket: AjaxLazyLoadPanel hangs after rendering first panel

Question

I'm using a Wicket AjaxLazyLoadPanel to render a list of items (each is its own panel). It works fine except when you navigate to the page in a fresh browser session (start browser up, go straight to this page without visiting any other pages in the app). When you do this, it renders the first item, but shows wait indicators for the other 12 forever.

Is this a bug in Wicket? I'm using version 1.4.9

Edit: Here is the way the LazyLoadPanel is being used. getLazyLoadComponent() only gets called once the first time you hit the page:

public void populateItem(final Item<ListSearchRow> item) {
  item.add(new AjaxLazyLoadPanel("result") {

    private static final long serialVersionUID = 1L;

    @Override
    public Component getLazyLoadComponent(String markupId) {
      return new ListResult(markupId, item.getModel());
    }  
  });
}