When I tried it, it does not turn off the indicators alone.  Instead it completely hides the row headers.  I want the row headers, I just do not want the graphic indicators.

 There's no property to hide the indicators without hiding the row selectors. You could probably acheive what you want using a DrawFilter, though. 

I'm probably too late on this, but it turns out that there is a way to hide the images:

        private void ultraGrid1_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {
            e.Layout.Override.RowSelectorAppearance.ImageAlpha = Alpha.Transparent;
        }