tonemarks display poorly sometimes

[ohnekopf]

Hi!
i'm pretty sure this is ultimately my fonts stack being stupid, but i get quite a few ill looking tonemarks:

(last one not as noticeable, tonemark slightly off center)

now i fixed this with kinda hackily by just using the .normalize method after rendering the popup (commit)
and got something a bit better looking:


anyway i guess a less hacky solution could be found (or i could fix my fonts). Antone else on linux (debian, firefox) having the same problem?