(Well crap, I can't get an image to work in this forum. Drive only gives a big red X. Dropbox will give a 32x32 but that's far too small to see the issue. The links work fine from other places, just not from writing a forum post here.)
Anyway, the issue appears to be the font used by PoL itself making the PoL window unusable.
Ubuntu 16.04.2 on a 3200x1800 display, with Universal Access / Large Text either ON or OFF. PoL 4.2.10.