When blurring with edge mode duplicate, duplicate the corner pixels in the corner areas of the filter region (top-left, top-right, bottom-left, and bottom-right). Also, when merging the duplicated areas, composite the cropped "view area" of SourceGraphic over the duplicated areas - instead of just SourceGraphic which could just write over the duplicated areas. Argh ...
When blurring with edge mode duplicate, duplicate the corner pixels in the corner areas of the filter region (top-left, top-right, bottom-left, and bottom-right). Also, when merging the duplicated areas, composite the cropped "view area" of SourceGraphic over the duplicated areas - instead of just SourceGraphic which could just write over the duplicated areas. Argh ...

nightjuggler/pig,nightjuggler/pig,nightjuggler/pig