<asp:UpdatePanel ID="upAgencyInfo" runat="server" UpdateMode="Conditional"> <Triggers> <asp:AsyncPostBackTrigger ControlID="AssignCaseToUser" EventName = "Click" /> </Triggers> <ContentTemplate> <table class="table_border1" width="100%" align="center" border="0" cellpadding="1" cellspacing="1" bgcolor="#ffffff" runat="server"> <tr class="TableHeader"> <td height="24" colspan="4" align="left"> <span class="blueText"> <asp:Label ID="lblAgencyTitle" runat="server" Text="Agency Information"></asp:Label></span> </td> </tr> <tr> <td height="24" class="SearchRowBlue" width="12%"> <span class="blackText"> <asp:Label ID="lblAgencyType" CssClass="blackText" Text="Auditor Name" runat="server" /></span> </td> <td height="24" class="SearchRowBlue1" colspan="3" width="42%"> <asp:Label ID="lblVendoName" CssClass="LableText" runat="server" /> </td> </tr> </table> </ContentTemplate> </asp:UpdatePanel>This is my second update panel where i put my User control. <asp:UpdatePanel ID="upAgencyEntry" runat="server" UpdateMode="Conditional"> <ContentTemplate> <asp:Panel ID="pnlAssignDesigUser" runat="server" CssClass="modalPopup" Width="40%" Style="display: none"> <AssignCase:AssignCase ID="AssignCaseToUser" runat="server" /> </asp:Panel> </ContentTemplate> </asp:UpdatePanel>Here "AssignCaseToUser" contains "btnSave" and "BtnSave_Click()" event.