Losing focus after AutoPostBack in UpdatePanel RSS

<asp:UpdatePanel ID="FirstUpdate" runat="server">
    <contenttemplate>
                    <table ID="STable"  runat="server" style="width:78%;">
                        <tr>
                            <td>
                                <asp:Label ID="Label6" runat="server" Text="Engine Select:">
                                <br />
                            </td>
                            <td class="style52">
                                 </td>
                            <td class="style55">
                                <asp:Label ID="Label3" runat="server" Text="Label" Visible="False">
                            </td>
                            <td class="style53" rowspan="12">
                                <div ID="MyDiv"  runat="server" 
                                    style="width: 160%; height: 356px;  overflow: scroll">
                                    <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" 
                                        GridLines="None" PageSize="25" style="margin-left: 0px" Width="96%">
                                        <alternatingrowstyle backcolor="White" forecolor="#284775" />
                                        <editrowstyle backcolor="#999999" />
                                        <footerstyle backcolor="#5D7B9D" font-bold="True" forecolor="White" />
                                        <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                                        <pagerstyle backcolor="#284775" forecolor="White" horizontalalign="Center" />
                                        <rowstyle backcolor="#F7F6F3" forecolor="#333333" />
                                        <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                                        <sortedascendingcellstyle backcolor="#E9E7E2" />
                                        <sortedascendingheaderstyle backcolor="#506C8C" />
                                        <sorteddescendingcellstyle backcolor="#FFFDF8" />
                                        <sorteddescendingheaderstyle backcolor="#6F8DAE" />                           
                            </td>
                        </tr>
                        <tr>
                            <td>
                                 </td>
                            <td class="style52">
                                 </td>
                            <td class="style55">
                                 </td>
                        </tr>
                        <tr>
                            <td class="style44" rowspan="4">
                                <asp:ListBox ID="ListBox1" runat="server" Height="148px" 
                                    SelectionMode="Multiple" style="margin-top: 0px" Width="188px">
                                
                               <%-- <Ajax:ListSearchExtender ID="ListBox1_ListSearchExtender"  runat="server" 
                                    Enabled="True" TargetControlID="ListBox1">
                                --%>
                            </td>
                            <td class="style52">
                                <asp:Button ID="ADD_ALL" runat="server" onclick="ADD_ALL_Click" Text=">>" 
                                    Width="72px" />
                            </td>
                            <td class="style55" rowspan="4">
                                <asp:ListBox ID="ListBox2" runat="server" Height="148px" 
                                    SelectionMode="Multiple" style="margin-left: 0px" Width="188px">
                                
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="ADD" runat="server" onclick="ADD_Click" Text=">" 
                                    Width="72px" />
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="Remove" runat="server" onclick="Remove_Click" Text="<" 
                                    Width="72px" />
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="Remove_ALL" runat="server" onclick="Remove_ALL_Click" 
                                    Text="<<" Width="72px" />
                            </td>
                        </tr>
                        <tr>
                            <td class="style44">
                                <asp:Label ID="Label2" runat="server" Text="Tag Select:">
                                <br />
                            </td>
                            <td class="style52">
                                 </td>
                            <td class="style55">
                                <asp:Label ID="Label7" runat="server" Text="Label" Visible="False">
                            </td>
                        </tr>
                        <tr>
                            <td class="style44">
                                 </td>
                            <td class="style52">
                                 </td>
                            <td class="style55">
                                 </td>
                        </tr>
                        <tr>
                            <td class="style44" rowspan="4">
                                <asp:ListBox ID="ListBox3" runat="server" Height="148px" 
                                    SelectionMode="Multiple" style="margin-top: 0px" Width="188px">
                                
                               <%-- <Ajax:ListSearchExtender ID="ListBox3_ListSearchExtender"  runat="server" 
                                    Enabled="True" TargetControlID="ListBox3">
                                --%>
                            </td>
                            <td class="style52">
                                <asp:Button ID="TAG_ADD_ALL" runat="server" onclick="TAG_ADD_ALL_Click" 
                                    Text=">>" Width="72px" />
                            </td>
                            <td class="style55" rowspan="4">
                                <asp:ListBox ID="ListBox4" runat="server" Height="148px" 
                                    SelectionMode="Multiple" style="margin-left: 0px" Width="188px">
                                
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="TAG_ADD" runat="server" onclick="TAG_ADD_Click" Text=">" 
                                    Width="72px" />
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="TAG_REMOVE" runat="server" onclick="TAG_REMOVE_Click" 
                                    Text="<" Width="72px" />
                            </td>
                        </tr>
                        <tr>
                            <td class="style52">
                                <asp:Button ID="TAG_REMOVE_ALL" runat="server" onclick="TAG_REMOVE_ALL_Click" 
                                    Text=">>" Width="72px" />
                            </td>
                        </tr>
                    
    </contenttemplate>