Comment 4 for bug 20921

Apparantly Qt3 only does font substitution if a whole character set is missing from the font.
With Polish and other eastern European fonts it has enough of the character set from Vera that
it doesn't bother finding substitutions for the missing characters. You can get round this by
installing a more complete font such as the Vera variant DejaVu (the ttf-dejavu package from
Debian unstable installs fine) and setting that as default.