Greek letters (unicode) are missing in the side panel

If adding text to a song and you want to use ancient greek letters of the alphabet,
in "insert special characters" button, you can only do that in choosing DejaVu Sans font.

In the default font: Edwin the unicode letters for ancient greek are missing.
If you select: DejaVu Sans fonts, the unicode letters show up.
If you select FreeSerif font, most of the characters are displayed with only a handful of glyphs missing.
The other fonts I haven´t checked.

That´s for your information
( I put it into the German forum by mistake)