Why?

Why is it that the example below works just fine, but if I move the updatepanel anywhere else, it stops working? It won't work if I put it directly below the asp:Panel. It won't work if I put it inside the <table>... Is there some rule I should be following here for where an updatepanel should be placed?

<asp:Panel ID="pnlOptions2" runat="server"> <tr> <td valign="top"><strong>Additional Options</strong></td> <td colspan="2"> <asp:UpdatePanel ID="upOptions2" runat="Server"> <ContentTemplate> <table cellpadding="0" cellspacing="0" width="650"> <tr> <td width="175"><asp:CheckBox ID="cbTransparencies" runat="server" Checked="false" AutoPostBack="true" />Transparencies</td> <td width="125"><asp:CheckBox ID="cbLetter" runat="server" checked="false" AutoPostBack="true" />Letter</td> <td width="175"><asp:CheckBox ID="cb11x171" runat="server" checked="false" AutoPostBack="true" />11x17 1's</td> <td width="175"><asp:CheckBox ID="cbPaper" runat="Server" checked="false" AutoPostBack="true" />Provided Paper</td> </tr> <tr> <td><asp:CheckBox ID="cbNCR2" runat="Server" checked="false" AutoPostBack="true" />2 part NCR</td> <td><asp:CheckBox ID="cbLabels" runat="server" checked="false" AutoPostBack="true" />Labels</td> <td><asp:CheckBox ID="cb11x172" runat="server" checked="false" AutoPostBack="true" />11x17 2's</td> <td><asp:CheckBox ID="cbLaminate" runat="server" checked="false" AutoPostBack="true" />Laminate</td> </tr> <tr> <td><asp:CheckBox ID="cbNCR3" runat="Server" checked="false" AutoPostBack="true" />3 part NCR</td> <td><asp:CheckBox ID="cbTabs" runat="server" checked="false" AutoPostBack="true" />Tabs</td> <td><asp:CheckBox ID="cbCards" runat="server" checked="false" AutoPostBack="true" />Business Cards</td> </tr> <tr> <td><asp:CheckBox ID="cbNCR4" runat="Server" checked="false" AutoPostBack="true" />4 part NCR</td> <td><asp:CheckBox ID="cbCerts" runat="server" checked="false" AutoPostBack="true" />Certs</td> <td><asp:CheckBox ID="cbBrochures" runat="server" checked="false" AutoPostBack="true" />Brochures</td> </tr> </table> </ContentTemplate> </asp:UpdatePanel> </td> </tr> </asp:Panel>

The UpdatePanel prefer to work within a DIV or a SPAN object. Try setting the RenderMode property of the UpdatePanel toInline

See it here for RenderMode property, try to set it

http://www.asp.net/AJAX/Documentation/Live/mref/P_System_Web_UI_UpdatePanel_RenderMode.aspx

See for most common problem of UpdatePanel

http://blogs.visoftinc.com/archive/2007/09/23/asp.net-ajax--updatepanel-not-working--common-problems.aspx