https://bugs.winehq.org/show_bug.cgi?id=55132
--- Comment #4 from pernegger@gmail.com --- So much for "easy to reproduce" ...
Japanese locale is set.
There's a full set of (Japanese) Windows TrueType fonts in the fontconfig search path, though I suppose this kind of dialogue might still use bitmap fonts?
Is there any way to find out what exactly it's missing?
Anyway, thanks for looking into this.