AJAX :: AjaxControlToolkit's ModalPopup Controls With Saving Updated Detailsview

For my project, i have decided to use AjaxControlToolkit's ModalPopup controls. I have obtains codes from this website: [URL] After following all the steps provided by Matt, I am getting some problems when i want to save my edited information. Scenario 1: Select the first item from the gridview, modify the details at the details view and click save, gridview updates and shows the edited information and it is stored into the database.

Scenario 2: Select the second item onwards from the gridview, modify the details at the details view and click save, screen remains at detailsview and edited information is not saved, click cancel button to return to gridview, data at the gridview was not updated. So basically, the update function works only for the first item from the gridview. The following is parts of my code:

<%-- Display list of Activities according to the Project--%>
<asp:UpdatePanel ID="UP_ActList" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:GridView ID="GV_ActList" runat="server" AutoGenerateColumns="False"
DataSourceID="SqlDS_ActList" DataKeyNames="dbID"
OnSelectedIndexChanged="GV_ActList_SelectedIndexChanged">
<RowStyle BackColor="#EFF3FB" />
<Columns>
<asp:BoundField DataField="dbID" HeaderText="dbID" Visible="false"
SortExpression="dbID" ReadOnly="true" InsertVisible="False" />
<asp:BoundField DataField="ActID" HeaderText="ActID"
SortExpression="ActID" />

.......Other BoundField were deleted for this post purpose............

<ItemTemplate>
<asp:LinkButton ID="LinkB_ViewActDetails" runat="server"
Text="Edit" CommandName="Select" CausesValidation="false"></asp:LinkButton>
</ItemTemplate>..............