มือใหม่ Ajax ค้าบขอคำปรึกษาหน่อยครับ เกี่ยวกับการกำหนดพื้นที่ Loading

    <div id="div1" style="height: 190px; position: relative;">
        <!-- Only this area is updated on PostBack -->
        <asp:UpdatePanel ID="updatePnl" runat="server" UpdateMode="Conditional">
            <ContentTemplate>
                <asp:GridView ID="gridViewPersons" runat="server" AutoGenerateColumns="False" CellPadding="4"
                    ForeColor="#333333" GridLines="None" Width="460px">
                    <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <Columns>
                        <asp:BoundField DataField="Surname" HeaderText="Surname" InsertVisible="False" ReadOnly="True">
                            <HeaderStyle HorizontalAlign="Left" />
                        </asp:BoundField>
                        <asp:BoundField DataField="Name" HeaderText="Name" InsertVisible="False" ReadOnly="True">
                            <HeaderStyle HorizontalAlign="Left" />
                        </asp:BoundField>
                        <asp:BoundField DataField="Street" HeaderText="Street" InsertVisible="False" ReadOnly="True">
                            <HeaderStyle HorizontalAlign="Left" />
                        </asp:BoundField>
                    </Columns>
                    <RowStyle BackColor="#EFF3FB" />
                    <EditRowStyle BackColor="#2461BF" />
                    <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                    <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                    <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <AlternatingRowStyle BackColor="White" />
                </asp:GridView>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="lbFilter" />
            </Triggers>
        </asp:UpdatePanel>
        <br />
        <asp:UpdateProgress ID="udProgress" runat="server" DisplayAfter="100" Visible="true"
            DynamicLayout="true">
            <ProgressTemplate>
                <div style="position: absolute; top: 30%; text-align: center;">
                    <img src="img/loading.gif" style="vertical-align: middle" alt="Processing" />
                    Processing ...
                </div>
            </ProgressTemplate>
        </asp:UpdateProgress>
    </div>
    <div id="div2" style="position: relative;">
        <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
            <ContentTemplate>
                <div>
                    <asp:TextBox ID="Text_Bocx" runat="server"></asp:TextBox>
                </div>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="lbFilter" />
            </Triggers>
        </asp:UpdatePanel>
    </div>

    <div id="div2" style="position: relative;">
        <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
            <ContentTemplate>
                <div>
                    <asp:TextBox ID="Text_Bocx" runat="server"></asp:TextBox>
                </div>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="lbFilter" />
            </Triggers>
        </asp:UpdatePanel>

        <asp:UpdateProgress ID="udProgress" runat="server" DisplayAfter="100" Visible="true"
            DynamicLayout="true">
            <ProgressTemplate>
                <div style="position: absolute; top: 30%; text-align: center;">
                    <img src="img/loading.gif" style="vertical-align: middle" alt="Processing" />
                    Processing ...
                </div>
            </ProgressTemplate>
        </asp:UpdateProgress>
    </div>

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="Panel1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="Panel1" LoadingPanelID="RadAjaxLoadingPanel1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
            <telerik:AjaxSetting AjaxControlID="CheckBox1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadAjaxLoadingPanel1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
            <telerik:AjaxSetting AjaxControlID="DropDownList1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadAjaxLoadingPanel1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>