I get these default screen fonts with lyx-1.4cvs qt: Roman: serif (ok) Sans serif: Abandoned Bitplane (ouch) Typewriter: Monospace (ok)
I have plenty of fonts installed, so this particularly bad font is avoidable. (The font is ok for special effects, it is unuseable in normal text. Just try looking up a keypress description in the userguide using this sans serif font, and cry.)
It looks like lyx simply used the first font in the fontlist, "abandoned bitplane" is indeed first in the list. I changed it to "Impact" which looks ok, although it is considerably narrower than the font used in the output.
The sans serif font is used on the splash screen also, and looks strange there too.
If it is hard selecting a good font from whatever is available, consider putting some advice and recommendations in the README. Distro packagers can then add dependencies for some useable fonts so lyx will come up ok when started for the first time.
Helge Hafting
Helge Hafting