Updatepanel works as expected in asp.net dev server (vstudio2010) and refreshes whole page on IIS7/2008

I've got a rudimentary example from MSoft of an updatepanel. When I do a Ctrl+F5 to test locally on my VSTUDIO 2010 box I scroll down and hit the "Refresh Panel" button listed below and it updates without having to scroll back down. When I "publish" the site to my Server2008/IIS7 box I scroll down, hit the button, and have to scroll down the page again to see that the updatepanel has actually refreshed, but so has the whole page. I just updated the .net framework on the server today to the latest release and the site has an asp.net 4.0 application pool running in Integrated Pipeline Mode. Help? Is this a problem with dll references, web.config, bin folder?

 <asp:ScriptManager ID="ScriptManager1" runat="server">
 </开发者_如何学运维asp:ScriptManager>
 <asp:UpdatePanel ID="UpdatePanel1" 
                 UpdateMode="Conditional"
                 runat="server">
    <ContentTemplate>
       <fieldset>
       <legend>UpdatePanel content</legend>
        <!-- Other content in the panel. -->
        <%=DateTime.Now.ToString() %>
        <br />
        <asp:Button ID="Button1" 
                    Text="Refresh Panel" 
                    runat="server" />
        </fieldset>
    </ContentTemplate>
</asp:UpdatePanel>

Moved the script to an IIS7.5/Server 2008(R2) box and it worked fine. Not sure what I would have had to install on the 2008 box to make it work, but even updating the .NET framework to 4.0 didn't do the trick. Shrug.