Please try to add a line
# -*- coding: utf-8 -*-
as the first line of your source file. I would like to see, if the character encoding is
set correctly. All text drawing is done by the QScintilla editor widget. However, it might
be initialized incorrectly, although I never saw such an issue on any of my systems
(Windows 7 and 10, various Linux and macOS).
In which version did it work? What was updated since then?