Hello Frans S,
Thanks for your double check and comment. It is good for me to be even more alert to the "squaring" of buildings. It is always difficult to make a proper assessment of whether it is a real building or whether it concerns storage of hay or reed. In fact, I have regularly considered switching steps on JOSM, but still I am having problems with my laptop by starting up the JOSM program. I will it try again. Best regards.