title: Ajax.BeginForm UpdateTargetId doesn't work with DropDownList
body: <p>Code:</p>
  
  <pre><code>&lt;% using (Ajax.BeginForm("GetResourcesByProject", "CreateRequest", new AjaxOptions { UpdateTargetId = "ResourceListDiv"}))
  {
   Response.Write(Html.DropDownList("SelectProject", Model.ProjectList, "Select Project", new { onchange = "this.form.submit();" }));
  } %&gt;
  </code></pre>
  
  <p>When I run the page I get the correct controller action to trigger with the right data in the form collection:</p>
  
  <pre><code>public ActionResult GetResourcesByProject(FormCollection formCollection)
  {
      var resourceModels = (from project in POTSModel.ProjectList
                            where project.Id == Convert.ToInt32(formCollection["SelectProject"])
                            select project).First().Resources;
  
      return PartialView("ResourceList", resourceModels);
   }
  </code></pre>
  
  <p>It works fine from an Ajax.ActionLink like this:</p>
  
  <pre><code>&lt;%= Ajax.ActionLink("Select", "GetResourcesByProject", "CreateRequest", new { projectId = item.Id }, new AjaxOptions { UpdateTargetId = "ResourceListDiv" })%&gt;
  </code></pre>
  
  <p>When the post happens I'm navigated to a new page instead of staying on the existing page and updating the contents of the div.</p>
  
  <p>Thanks.</p>