When i delete line
fallback.4=…\texture\Glass
from texture.cfg, whole glass window transforms in sim to kind a rainbow poster. So correct .dds file has to be in that xxx\AppData\Roaming\Microsoft Flight Simulator\Packages\Official\Steam\fs-base\texture\GLASS folder, but i allready edited all of those there to be transparent and still glass is showing.
So it has to be elsewhere then.