title: Why does Update Progress does not fire when AssociatedUpdatePanelId is set?
body: <p>When I assign the AssociatedUpdatePanelId, the progress does not display when I select a state, but when I leave it blank, it displays the progress.</p>
  
  <p>Here is the aspx markup:</p>
  
  <pre><code>&lt;div&gt;
      &lt;asp:ListBox ID="lstStates" runat="server" AutoPostBack="True"
      OnSelectedIndexChanged="lstStates_SelectedIndexChanged" SelectionMode="Multiple"&gt;
      &lt;/asp:ListBox&gt;
  &lt;/div&gt;
  &lt;div&gt;
      &lt;asp:UpdatePanel ID="UpdatePanel1" runat="server"&gt;
      &lt;ContentTemplate&gt;
      &lt;asp:Panel ID="pnlCounty" runat="server"&gt;
      &lt;asp:ListBox ID="lstCounties" runat="server" SelectionMode="Multiple"&gt;
      &lt;/asp:ListBox&gt;
      &lt;/asp:Panel&gt;
      &lt;/ContentTemplate&gt;
      &lt;Triggers&gt;
      &lt;asp:AsyncPostBackTrigger ControlID="lstStates" EventName="SelectedIndexChanged" /&gt;
      &lt;/Triggers&gt;
      &lt;/asp:UpdatePanel&gt;
      &lt;asp:UpdateProgress ID="UpdateProgress2" runat="server" DisplayAfter="1"
                          AssociatedUpdatePanelID="UpdatePanel1"&gt;
      &lt;ProgressTemplate&gt;
      &lt;img src="../images/loader2.gif" /&gt;
      Loading Counties...
      &lt;/ProgressTemplate&gt;
      &lt;/asp:UpdateProgress&gt;
  &lt;/div&gt;
  </code></pre>