Entering a vertical array ={10;20} works ok, but horizontal array ={10,20}
gives 10,2 ;-) in both cells instead of 10 and 20 in the two cells.

This happens, I presume, because I work with a comma as decimal separator
and NOT with the American .
I do suppose that Excel has got some solution for this behaviour.
I, in principle, do NOT want to change the regional options.