I have this RadComboBox (ddlSrvTypCde) that triggers the radajaxmanager but I don't want the controls on the last <tr></tr> to get affected. I tried putting PostBackControls but it doesn't work.

//
        function centerLoadingPanel(ajaxManager, eventArgs) {
            centerElementOnScreen($get("<%= AjaxLoadingPanel.ClientID %>"));
        }

//


<telerik:RadAjaxManager ID="RadAjaxManager" PostBackControls="txtAFPCde, txtAFPCdeName, ButtonDialogAFPCde, btnAFPCde, txtAFPCdeVal, txtAFPCdeNameVal, txtAFPCdeId" runat="server">
<ClientEvents OnRequestStart="centerLoadingPanel"></ClientEvents>
</telerik:RadAjaxManager>


<asp:Panel ID="pnlAllowed" runat="server" Visible="true">

<telerik:RadAjaxLoadingPanel ID="AjaxLoadingPanel" PostBackControls="txtAFPCde, txtAFPCdeName, ButtonDialogAFPCde, btnAFPCde, txtAFPCdeVal, txtAFPCdeNameVal, txtAFPCdeId" runat="server" />
<asp:Panel ID="AjaxUpdateStub" runat="server">

<telerik:RadMultiPage runat="server" ID="multiService" SelectedIndex="0" SkinID="RadMultiPageModalForm" Height="315px">
<telerik:RadPageView runat="server" ID="pgeType">
<div class="FormTabSpacer">
<table class="FormHeaderInnerTable">
<tr>
<td>
<table style="width: 500px">
<tr>
<td style="text-align: right; width: 140px;">
<asp:Label ID="lblServiceType" runat="server" Text="Service Type" "></asp:Label>
</td>
<td style="text-align: left; width: 320px;">
<telerik:RadComboBox ID="ddlSrvTypCde" runat="server" Width="317px" TabIndex="3" AutoPostBack="true" CausesValidation="false">
</telerik:RadComboBox>
</td>
</tr>
<tr>
<td class="FormColumnCellLeft">&nbsp;
</td>
<td class="FormColumnCellRight">
<asp:CheckBox ID="chkAllowFractions" runat="server" TabIndex="4" Text="Service"  Style="display: none" />
</td>
</tr>

<tr>
<td class="FormColumnCellLeft">&nbsp;
</td>
<td class="FormColumnCellRight">
<asp:CheckBox ID="chkUseTier" runat="server" Text="Tiered Pricing" TabIndex="6" />
</td>
</tr>

<tr>
<td class="FormColumnCellLeft">&nbsp;
<asp:Label ID="lblAFPCde" runat="server" Text="AFP Code" ></asp:Label>&nbsp;
</td>
<td class="FormColumnCellRight">
<asp:TextBox ID="txtAFPCde" runat="server" Width="50px" ReadOnly="True" SkinID="disabledtextbox"></asp:TextBox>
<asp:TextBox ID="txtAFPCdeName" runat="server" ReadOnly="True" SkinID="disabledtextbox" Width="193px" TabIndex="999"></asp:TextBox>
<input id="ButtonDialogAFPCde" runat="server" name="ButtonDialogAFPCde" style="width: 20px;" type="button" value="..." tabindex="8" />
<asp:Button ID="btnAFPCde" runat="server" SkinID="pickupbutton" Visible="False" TabIndex="999" />
<asp:TextBox ID="txtAFPCdeVal" runat="server" Width="70px" TabIndex="999"></asp:TextBox>
<asp:TextBox ID="txtAFPCdeNameVal" runat="server" Width="220px" TabIndex="999"></asp:TextBox>
<asp:TextBox ID="txtAFPCdeId" runat="server" Width="70px" TabIndex="999"></asp:TextBox>

</td>
</tr>

Hi Voltaire,

All possible ways to exclude the desired controls from an AJAX update are listed in the following help article, so you can choose that one that fits your scenario the best:
https://docs.telerik.com/devtools/aspnet-ajax/controls/ajaxmanager/how-to/exclude-controls-from-ajaxifying

Regards,
Vessy
Progress Telerik