Sorry if this comes through twice.
I tested saving on my machine, using TextEdit, and Thai characters. My
string encoding is set to utf-8. And it worked. it saved anyways. I don't
have anything that will open it reasonably.
I also tried in Ink. It still didn't work. as I can't find any file saving
code in Ink, maybe this has somehing to do with NSDocument or
NSDocumentController.