[RMMV]NEED HELP FOR WINDOWSKIN TILED BACKGROUND!

Hiyas~!I'm making of a dating-like simulation game called Chingyoje MV,but I didn't like the windowskin background stretching to fit(the option to select between stretch and tiled display is not included in the YEP_MessageCore plugin).Do you have any ideas for setting the windowskin box background from stretch-to-fit to tiled display?

Thanks~!