Hello Michael,

thanks for looking into this :) Attached the earlier version where the items were still separate - the problem with union started with the four tiles (cboard_problems) trying to merge with the whole board (cboard_ok_sofar). I tried different things (with 'eyes closed' as no clue what was the cause of failing): scaling up/down, moving a bit, union with the legs etc but no help.

br Ari