P: I can't see chessboard transparency in layers thumbnail

Since the introduction of artboards I do not see transparency in the layers thumbnails.Compare:http://sklad.bereza.cz/00-jarda/00_sc... what is really therehttp://sklad.bereza.cz/00-jarda/00_sc... to view chessboard transparency in artboards?In the document without artboards it works correctly.http://sklad.bereza.cz/00-jarda/00_sc... is wrong in the case of white color, because I can not see it.If you delete all artboards, everything is again ok.