Why do you say they are clearly on line? Could well be making moves on a handheld device.
green square not there
Well I suppose so. Could that be why? I say 'online' because eg the opponent I'm playing now is replying to my moves straight away so surely they must be online but there's no green square. Would a handheld device somehow register differently at chess.com?
Why doesn't the green square always appear when my opponent is clearly on line? It's useful because it lets me know if it's worth waiting for the next move or if they've gone off line. For some opponents it's there, for some not.