setShowSortArrow(SortArrow.FIELD) and corner style

SmartClient Version: v9.1p_2014-06-04/Pro Deployment (built 2014-06-04)

I am hiding the corner sorter by setting setShowSortArrow(SortArrow.FIELD), however, I was hoping this would remove the sorter image, but leave the other visual appearances alone, specifically, leave the empty section above the scrollbar grey rather than make it an empty white section.

Is there an option for controlling this?

Thanks