Thank you for letting us know, this is a bug. I've logged it as Bug ID 28036285.
Seems to be fixed on 11.4 Beta Refresh 2 (July 2018),
as long as I checked on console, saved it and saw on desktop.
But, can not get Japanese on desktop this time.
See new discussion "ja_JP.UTF-8 locale on desktop"
Understand the reason why can not get Japanese on desktop.
I confirm this bus is fixed on Solaris 188.8.131.52.0.