Grid View goes blank after you close jquery modal popup

The code is on this link below

[Solved] Sys.WebForms.PageRequestManagerServerErrorException: Input string was not in a correct format

When i click on the close button on the jQuery modal popup, the grid view goes blank with no data. That is when i click on the view button, the jQuery modal popup pops out with data. When i click on the close button on the modal popup, the page displays the GridView without data.

I have to load the main page again to see the GridView, but i expect to see the page with GridView immediately i click the close button on the modal popup.

Please help

    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <asp:HiddenField ID="hfId" runat="server" />
            <asp:GridView ID="gvDetails" runat="server" AutoGenerateColumns="False"
                BackColor="White" BorderColor="#3366CC" BorderStyle="None"
                Font-Names="Century Gothic" Font-Size="XX-Small" DataKeyNames="id"
                Width="100%" Style="margin-bottom: 0px" CssClass="grid">
                <Columns>
                    <asp:TemplateField>
                        <ItemTemplate>
                            <asp:CheckBox ID="chkSelect" runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                   <asp:BoundField DataField="id" HeaderText="id" />
                    <asp:BoundField DataField="pid" HeaderText="pid" />
                    <asp:BoundField DataField="description" HeaderText="Description" />
                    <asp:BoundField DataField="country" HeaderText="country" />
                    <asp:BoundField DataField="pack" HeaderText="pack" />
                    <asp:BoundField DataField="customer" HeaderText="customer" />
                    <asp:BoundField DataField="jobnumber" HeaderText="jobnumber" />
                    <asp:BoundField DataField="artworkdate" HeaderText="artworkdate" />
                    <asp:BoundField DataField="reprodate" HeaderText="reprodate" />
                    <asp:BoundField DataField="artworknumber" HeaderText="artworknumber" />
                    <asp:BoundField DataField="templateno" HeaderText="templateno" />
                     <asp:TemplateField>
                        <ItemTemplate>
                              
                            <asp:Button CssClass="view" Text="View" ID="Inkview" runat="server" OnClick="Inkview_Click"  ForeColor="white"  BackColor="#FF6600"/>
                        </ItemTemplate>
                           
                    </asp:TemplateField>
                     <asp:TemplateField>
                        <ItemTemplate>
                      <asp:Button  CssClass="view" Text="Edit" ID="lnkView1" runat="server" OnClick="Inkview_Click1"     ForeColor="white"  BackColor="#FF6600"/>
                 </ItemTemplate>
                    </asp:TemplateField>
          
                </Columns>
                <HeaderStyle BackColor="green" Font-Bold="True" ForeColor="#CCCCFF" />
                <PagerStyle BackColor="#99CCCC" ForeColor="#003399" HorizontalAlign="Left" />
                <RowStyle BackColor="White" ForeColor="#003399" />
                <SelectedRowStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />
                <SortedAscendingCellStyle BackColor="#EDF6F6" />
                <SortedAscendingHeaderStyle BackColor="#0D4AC4" />
                <SortedDescendingCellStyle BackColor="#D6DFDF" />
                <SortedDescendingHeaderStyle BackColor="#002876" />
            </asp:GridView>
        </ContentTemplate>
    </asp:UpdatePanel>