Comment 4 for bug 1515430

I have a very similar problem with plank, however, I can actually see the line where the windows dock, which is very annoying.

The line disappears when I quit plank.

This happens on all screens, on all orientations and independent of auto-hide - short: always.

My setup:
Manjaro Linux 16.06.1
xfce 4.12
plank 0.11.2

Is this an also an issue with xfwm, or does that come from the more recent plank version?