This worked well, thanks!

For reference if anyone is trying to do the same, here's what I did:

1) Did a BareGrep and found the style for "LabelPresenter" in:

C:\Program Files (x86)\Infragistics\NetAdvantage for .NET 2009.1\WPF\DefaultStyles\DataPresenter
DataPresenterGeneric_Express.xaml

2) Copied the style to my resources:

<Style x:Key="NoSortIndicatorStyle" TargetType="{x:Type igDP:LabelPresenter}">
...
</Style>

3) Copied a couple of converters used by the above style to my resources:

    <igDP:TextAlignmentToHorizontalAlignmentConverter x:Key="textAlignmentToHorizontalAlignmentConverter"/>
    <BooleanToVisibilityConverter x:Key="BoolToVisConverter"/>

In this case, you should set x:key to the style and apply the style only to that Field. If you do not set x:key, the style will be applied to all the fields. 

<Style x:Key="NoSortIndicatorStyle" TargetType="{x:Type igDP:LabelPresenter}" >

....

and apply the style to the LabelPresenter in the Settings of the field like this:

<igDP:UnboundField Name="index" Label="index" BindingPath="CustomerName">

                            <igDP:UnboundField.Settings>

                                <igDP:FieldSettings LabelPresenterStyle="{StaticResource NoSortIndicatorStyle}"/>

                            </igDP:UnboundField.Settings>

                        </igDP:UnboundField>

Note: Type of the field : unbound or just Field makes no difference.

Alex.

Hi Alex,

Thanks for the response - I'll try it out.

But just to make sure: would your solution remove the SortIndicator for all headers/columns?  I need to remove the SortIndicator only for one specific narrow column.