why selectedrowstyle of a gridview is not shown when doing asyncpostback?
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I have a gridview which contains a select commandfield.

I also have an updatepanel which contains a details view.

The gridview is outside update panel.

I want when selected button is pressed the selected row of the gridview to change color and the details to be shown in the details view without page refreshing. 

Here is my code:

    		<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Column1" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:CommandField HeaderText="details" ShowSelectButton="True" />
                <asp:BoundField DataField="Column1" HeaderText="Column1" SortExpression="Column1" />
            </Columns>
            <SelectedRowStyle BackColor="#FFFFFF" />
        </asp:GridView>
		
		
		<asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:DetailsView ID="DetailsView1" runat="server" AutoGenerateRows="False" DataKeyNames="Column1" DataSourceID="SqlDataSource2"  Height="50px" Width="125px">
                    <Fields>
                        <asp:BoundField DataField="Column1" HeaderText="Column1" InsertVisible="False" ReadOnly="True" SortExpression="Column1" />
                        <asp:BoundField DataField="Column2" HeaderText="Column2" SortExpression="Column2" />
                    </Fields>
                </asp:DetailsView>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="GridView1" />
            </Triggers>
        </asp:UpdatePanel>

The problem is that gridview does not change the color of the selected row when it is outside the update panel.
I know that when i move it inside the updatepanel it will work but I want to know why this happens.

Thanks.