Ah, maybe it was Ctrl-U and not Ctrl-O that was the "space" that I was talking about. I haven't used it for a long time because that was such a problem.
I think that if mIRC could change the Ctrl-U character so that it wasn't a space/blank in the Asian language codepage, then it would work out well. The problem with that is that, to do so, you'd have to change the $chr used for it and that would break scripts and wouldn't be compatible with other clients unless mIRC worked behind the scenes on it and just converted it for internal use. No idea... just commenting on the issue. Having the codes a different color or something would definitely help to make it easier to see the difference.