I sometimes have thin vertical glitches on windows 8 with zoom at 125% (everything seems ok windows 7)
A simple way to reproduce is to launch the DemoRunner (keep its default size, don’t resize it) -> flew box demo
and click the “column-reverse” option.
just a shot in the dark, can it be related to this issue (which I still think its a bug, but Jules denies)
PS: could also be something different.