Thanks to Dev Support, the ExpandAll works now.  You have to put the ExpandAll in the NodeBound event handler.

In C#

     protected void UltraWebTree1_NodeBound(object sender, Infragistics.WebUI.UltraWebNavigator.WebTreeNodeEventArgs e)
    {
        this.UltraWebTree1.ExpandAll();
    }

In aspx

          <ig:WebSplitter ID="WebSplitter1" runat="server" Height="519px" Width="808px">
            <Panes>
                <ig:SplitterPane runat="server" Size="200px">
                <Template>
                    <ignav:UltraWebTree ID="UltraWebTree1" runat="server"
                        DataSourceID="XmlDataSource1" DefaultImage="" 
                        Indentation="20" AutoPostBack="True" OnNodeBound="UltraWebTree1_NodeBound">
                        <DataBindings>
                            <ignav:NodeBinding DataMember="ParentTable" TargetUrlField="targetURL"
                                TextField="name" />
                            <ignav:NodeBinding DataMember="BaseTable" TargetUrlField="targetURL"
                                TextField="name" />
                        </DataBindings>
                    </ignav:UltraWebTree>
               
               
                    <asp:XmlDataSource ID="XmlDataSource1" runat="server"
                        DataFile="~/App_Data/TXLTaskList.xml"></asp:XmlDataSource>
                </Template>
                </ig:SplitterPane>
                <ig:SplitterPane runat="server" Size="100%">
                </ig:SplitterPane>
            </Panes>
        </ig:WebSplitter>

Hello,

I am trying to reproduce the issue with WebSpliter but I can`t observe described behavior. I believe at this point it is best to contact our Developer Support department directly - they can be reached at:
http://es.infragistics.com/support/
Please take a look at the picture below:

Thanks.

Hi Ivan,

 I have the same setup that you're testing with.  One thing I didn't mention in my initial question was my webtree is inside a websplitter.  So I have a websplitter with 2 panes.  The webtree is in one of the panes.  Could this be causing the webtree to not expand?

 Thanks,

John