Problem with UpdatePanel GridView refresh

Hi,
I have to refresh automatically a GridView. I use an UpdatePanel control and a Timer control.

This is my HTML code:

<asp:Timer ID="TMROrdiniInviati" runat="server" Interval="15000"></asp:Timer><asp:UpdatePanel ID="UPOrdiniInviati" runat="server" ChildrenAsTriggers="False" UpdateMode="Conditional" ViewStateMode="Enabled"><ContentTemplate>                                                <asp:GridView ID="GVOrdiniCorriereMG" runat="server" AutoGenerateColumns="False" BackColor="White" 
                                                        BorderColor="#999999" BorderStyle="None" BorderWidth="1px" CellPadding="3" 
                                                        DataSourceID="SDSOrdiniCorriereMG" 
                                                        DataKeyNames="IDOrdine" HorizontalAlign="Center" 
                                                        EmptyDataText="Nessun ordine inviato presente in archivio" Width="95%">
							........................
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							........................</asp:GridView><asp:SqlDataSource ID="SDSOrdiniCorriereMG" runat="server" ConnectionString="<%$ ConnectionStrings:AHR_PORTALE_sa_ConnectionString %>"                                 
							........................
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							........................                                                        </asp:SqlDataSource></ContentTemplate><Triggers><asp:AsyncPostBackTrigger ControlID="TMROrdiniInviati" EventName="Tick" />        	</Triggers></asp:UpdatePanel>

And this is my code-behind code:

Private Sub TMROrdiniInviati_Tick1(sender As Object, e As System.EventArgs) Handles TMROrdiniInviati.Tick
     GVOrdiniCorriereMG.DataBind()
End Sub

The GridView auto-refresh works fine every 15 seconds but I have a problem when I select a GridView row by clicking on a select column.

When I click to select a GridView row, the SelectedIndexChanged event is raised when the next Timer tick event occours... so I have to wait 15 second before the selection action is executed.

I have to refresh automatically the GridView but I have, also, to work with GridView rows normally...

Thank you very much!