carolannr Unless sun protection is a problem, I think it looks overdone to cover the whole window. Maybe because I'm a little claustraphobic but I like to see the blue sky if possible. I'm sure its a matter of opinion, no decorating law will be broken if you don't want to cover the whole thing.
Jean Tuck Do what feels nice to you. I would just cover the bottom square because of the arhed area and unless it would spoil privacy to leave this open .
There's your answer! ;)