Thanks for your reply Maya.  Below is the code.  I select a record from WebDataGrid1 and then display the data in the controls on the WebTab, 3 textboxes and a WebDataGrid.  I currently have all controls within an Updatepanel.  I did discover through some testing on Friday that if I remove the WebDataGrid from the WebTab, I do not get the "Invalid JSON primitive" error. 

I am in the process of converting the classic controls, i.e., UltraWebGrid, UltraWebTab, etc, to WebDataGrid, WebTab, etc to insure I can achieve the same functionality with the newer controls as with the classic controls.

<asp:UpdatePanel ID="UpdatePanel1" runat="server">

<ContentTemplate>

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

<ig:WebTab ID="WebTab1" runat="server" BackColor="White" BorderColor="Black" EnableViewState="False"

BorderStyle="Solid" BorderWidth="1px" Font-Names="Verdana" Font-Size="Medium" Height="400px" Width="900px" SelectedIndex="3">

<tabs>

<ig:ContentTabItem runat="server" Text="Employee Info" Key="Employee Info">

<Template>

<asp:Label ID="Label1" runat="server" Text="Employee ID" Font-Names="Verdana" Font-Size="Small"></asp:Label>

<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>

<asp:Label ID="Label2" runat="server" Text="Name Last" Font-Names="Verdana" Font-Size="Small"></asp:Label>

<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>

<asp:Label ID="Label3" runat="server" Text="First" Font-Names="Verdana" Font-Size="Small"></asp:Label>

<asp:TextBox ID="TextBox4" runat="server"></asp:TextBox>

</Template>

</ig:ContentTabItem>

<ig:ContentTabItem runat="server" Text="Emergency Contact" Key="Emergency Contact">

<Template>

</Template>

</ig:ContentTabItem>

<ig:ContentTabItem runat="server" Text="Education/Certifications" Key="Education/Certifications">

<Template>

</Template>

</ig:ContentTabItem>

<ig:ContentTabItem runat="server" Text="Contracts" Key="Contracts">

<Template>

<ig:WebDataGrid ID="WebDataGrid3" runat="server" AutoGenerateColumns="False"DataSourceID="SqlDataSource3" Height="350px" Width="800px" DataKeyFields="ContractSeq" EnableViewState="False">

<Columns>

<ig:BoundDataField DataFieldName="ContractSeq" Key="ContractSeq" Hidden="True" DataType="System.Int32">

<Header Text="ContractSeq" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="ContractID" Key="ContractID" Width="150px" DataType="System.String">

<Header Text="Contract ID" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="Title" Key="Title" Width="200px" DataType="System.String">

<Header Text="Title" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="ProjectNr" Key="ProjectNr" Width="150px" DataType="System.String">

<Header Text="Project Nr" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="Clin" Key="Clin" Width="100px" DataType="System.String">

<Header Text="Clin" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="EmployeeSeq" Key="EmployeeSeq" Width="100px" Hidden="true" DataType="System.Int32" >

<Header Text="EmployeeSeq" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="SubClin" Key="SubClin" Width="120px" DataType="System.String">

<Header Text="Sub Clin" />

</ig:BoundDataField>

</Columns>

<Behaviors>

<ig:EditingCore AutoCRUD="True">

<Behaviors>

<ig:CellEditing >

<CellEditingClientEvents EnteredEditMode="loadDropDownItems" />

<ColumnSettings>

<ig:EditingColumnSetting ColumnKey="ContractID" EditorID="DropDownProvider1"/>

<ig:EditingColumnSetting ColumnKey="ProjectNr" EditorID="DropDownProvider2" />

<ig:EditingColumnSetting ColumnKey="Clin" EditorID="DropDownProvider3" />

<ig:EditingColumnSetting ColumnKey="SubClin" EditorID="DropDownProvider4" />

</ColumnSettings>

<EditModeActions MouseClick="Single" />

<CellEditingClientEvents EnteredEditMode="loadDropDownItems"></CellEditingClientEvents>

</ig:CellEditing>

<ig:RowAdding Alignment="Top">

<EditModeActions MouseClick="Single" />

<AddNewRowClientEvents EnteredEditMode="loadDropDownItems" />

<ColumnSettings>

<ig:RowAddingColumnSetting ColumnKey="ContractID" EditorID="DropDownProvider1" />

<ig:RowAddingColumnSetting ColumnKey="ProjectNr" EditorID="DropDownProvider2" />

<ig:RowAddingColumnSetting ColumnKey="Clin" EditorID="DropDownProvider3" />

<ig:RowAddingColumnSetting ColumnKey="SubClin" EditorID="DropDownProvider4" />

</ColumnSettings>

<AddNewRowClientEvents EnteredEditMode="loadDropDownItems"></AddNewRowClientEvents>

</ig:RowAdding>

<ig:RowDeleting />

</Behaviors>

</ig:EditingCore>

<ig:Selection CellClickAction="Cell" RowSelectType="Single" >

<AutoPostBackFlags CellSelectionChanged="True" RowSelectionChanged="true" />

</ig:Selection>

<ig:RowSelectors>

</ig:RowSelectors>

<ig:Activation>

<ActivationClientEvents />

</ig:Activation>

</Behaviors>

<EditorProviders>

<ig:DropDownProvider ID="DropDownProvider1">

<EditorControl ID="EditorControl1" runat="server" ClientIDMode="Predictable" DropDownContainerMaxHeight="200px"

EnableAnimations="False" EnableDropDownAsChild="False" DropDownContainerWidth="600px" >

<Items>

<ig:DropDownItem Key="ContractID" >

</ig:DropDownItem>

</Items>

<ItemTemplate>

<ig:WebDataGrid ID="WebDataGrid4" runat="server" AutoGenerateColumns="true" DataSourceID="SqlDataSource2" Height="350px" Width="500px">

<Behaviors>

<ig:Selection CellClickAction="Row" RowSelectType="Single" SelectionClientEvents-RowSelectionChanged="WebDataGrid4_RowSelectionChanged">

</ig:Selection>

</Behaviors>

</ig:WebDataGrid>

</ItemTemplate>

</EditorControl>

</ig:DropDownProvider>

<ig:DropDownProvider ID="DropDownProvider2" >

<EditorControl ID="EditorControl2" runat="server" ClientIDMode="Predictable" DropDownContainerMaxHeight="200px" OnItemsRequested="eProvider_ItemsRequested" EnableAnimations="False" EnableDropDownAsChild="False" DropDownContainerWidth="400px" AutoPostBack="False">

<Items>

<ig:DropDownItem Key="ProjectNr" >

</ig:DropDownItem>

</Items>

</EditorControl>

</ig:DropDownProvider>

<ig:DropDownProvider ID="DropDownProvider3" >

<EditorControl ID="EditorControl3" runat="server" ClientIDMode="Predictable" DropDownContainerMaxHeight="200px" OnItemsRequested="eProvider_ItemsRequested" EnableAnimations="False" EnableDropDownAsChild="False" DropDownContainerWidth="200px" >

<Items>

<ig:DropDownItem Key="Clin" >

</ig:DropDownItem>

</Items>

</EditorControl>

</ig:DropDownProvider>

<ig:DropDownProvider ID="DropDownProvider4" >

<EditorControl ID="EditorControl4" runat="server" ClientIDMode="Predictable" DropDownContainerMaxHeight="200px" OnItemsRequested="eProvider_ItemsRequested" EnableAnimations="False" EnableDropDownAsChild="False" DropDownContainerWidth="200px" >

<Items>

<ig:DropDownItem Key="SubClin">

</ig:DropDownItem>

</Items>

</EditorControl>

</ig:DropDownProvider>

</EditorProviders>

</ig:WebDataGrid>

</Template>

</ig:ContentTabItem>

</tabs>

<ContentPane AutoSize="True">

</ContentPane>

</ig:WebTab>

<ig:WebDataGrid ID="WebDataGrid1" runat="server" Height="200px" Width="670px" AutoGenerateColumns="False" DataSourceID="SqlDataSource1" DataKeyFields="EmployeeSeq" StyleSetName="Default" EnableAjax="False" >

<Columns>

<ig:BoundDataField DataFieldName="EmployeeSeq" Key="EmployeeSeq" Hidden="True"

Width="100px" DataType="System.Int32">

<Header Text="EmployeeSeq" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="Employee Number" Key="Employee Number"

Width="150px" DataType="System.String">

<Header Text="Employee Number" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="Last Name" Key="Last Name" Width="100px" DataType="System.String">

<Header Text="Last Name" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="First Name" Key="First Name" Width="100px" DataType="System.String">

<Header Text="First Name" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="MI" Key="MI" Width="30px" DataType="System.String">

<Header Text="MI" />

</ig:BoundDataField>

<ig:BoundDataField DataFieldName="Suffix Name" Key="Suffix Name" Width="150px" DataType="System.String">

<Header Text="Suffix Name" />

</ig:BoundDataField>

</Columns>

<Behaviors>

<ig:Selection CellClickAction="Row" RowSelectType="Single">

<AutoPostBackFlags RowSelectionChanged="True" />

</ig:Selection>

<ig:RowSelectors>

</ig:RowSelectors>

<ig:Filtering Visibility="Visible" FilterButtonCssClass="hiddenCss">

<ColumnSettings>

<ig:ColumnFilteringSetting ColumnKey="Employee Number" Enabled="False" />

<ig:ColumnFilteringSetting ColumnKey="First Name" Enabled="False" />

<ig:ColumnFilteringSetting ColumnKey="Last Name" />

<ig:ColumnFilteringSetting ColumnKey="EmployeeSeq" Enabled="False" />

<ig:ColumnFilteringSetting ColumnKey="MI" Enabled="False" />

<ig:ColumnFilteringSetting ColumnKey="Suffix Name" Enabled="False" />

</ColumnSettings>

<ColumnFilters>

<ig:ColumnFilter ColumnKey="Last Name">

<ConditionWrapper>

<ig:RuleTextNode Rule="BeginsWith" />

</ConditionWrapper>

</ig:ColumnFilter>

</ColumnFilters>

</ig:Filtering>

<ig:Sorting>

<ColumnSettings>

<ig:SortingColumnSetting ColumnKey="Employee Number" Sortable="true" />

<ig:SortingColumnSetting ColumnKey="First Name" Sortable="true" />

<ig:SortingColumnSetting ColumnKey="Last Name" Sortable="true" />

<ig:SortingColumnSetting ColumnKey="EmployeeSeq" Sortable="false" />

<ig:SortingColumnSetting ColumnKey="MI" Sortable="false" />

<ig:SortingColumnSetting ColumnKey="Suffix Name" Sortable="false" />

</ColumnSettings>

</ig:Sorting>

</Behaviors>

</ig:WebDataGrid>

</ContentTemplate>

<Triggers>

<asp:AsyncPostBackTrigger ControlID="WebDataGrid1" EventName="RowSelectionChanged" />

</Triggers>

</asp:UpdatePanel>

Private Sub WebDataGrid1_RowSelectionChanged(sender As Object, e As Infragistics.Web.UI.GridControls.SelectedRowEventArgs) Handles WebDataGrid1.RowSelectionChanged

Dim selectedRows As SelectedRowCollection = WebDataGrid1.Behaviors.Selection.SelectedRows

For Each row As GridRecord In selectedRows

Session(

"EmployeeSeq") = row.Items.Item(0).Text

TextBox1.Text = row.Items.Item(0).Text

Dim dbEmployees = (From employees In dbHumanResources.Employees _

Where employees.EmployeeSeq = Session("EmployeeSeq").ToString _

Select employees).ToList

If dbEmployees.Count > 0 Then

End If

Next

End Sub

I have narrowed things down since my earlier post.  The problem appears to be with a dropdownprovider within my webdatagrid on one of my tabs.  Within the dropdownprovider, I have an itemtemplate defined using a webdatagrid so as to have a multicolumn dropdown.  Here is the code

<ig:DropDownProvider ID="DropDownProvider1">

<EditorControl ID="EditorControl1" runat="server" ClientIDMode="Predictable" DropDownContainerMaxHeight="200px" EnableAnimations="False" EnableDropDownAsChild="False" DropDownContainerWidth="600px">

<Items>

<ig:DropDownItem Key="ContractID" >

</ig:DropDownItem>

</Items>

<ItemTemplate>

<ig:WebDataGrid ID="WebDataGrid4" runat="server" AutoGenerateColumns="true" DataSourceID="SqlDataSource2" Height="350px" Width="500px">

<Behaviors>

<ig:Selection CellClickAction="Row" RowSelectType="Single" SelectionClientEvents-RowSelectionChanged="WebDataGrid4_RowSelectionChanged">

</ig:Selection>

</Behaviors>

</ig:WebDataGrid>

</ItemTemplate>

</EditorControl>

</ig:DropDownProvider>

Not sure why I get the "Invalid JSON primitive" error yet, but have at least narrowed down to where the problem may be.

Thanks Maya!

Thanks Maya.  I got sidetracked on another project and have not had a chance to get back to this.  I don't think I explained my problem very well.  I actually think the issue has something to do with using an UpdatePanel with the WebDataGrid.  Get back with you on this soon.  Thanks again.