Created attachment 32164 [details] suggested patch XSSFDrawing.createCellComment() takes a ClientAnchor as an argument to control positioning of the created comment. While it positions the comment at the given cells it completely ignores any dx and dy values defined in the anchor and sets those to 0 on the resulting VML-drawing. See my attached patch for how I think it should work.
Thank you for the patch. Applied with r1639996 I've changed that patch, so that the dx/dy values are specified as EMUs (opposed to pixels) to be in line with other client anchor usages in XSSF. I've moved the client anchor tests for xssf/hssf to the common base class.