Comment 4 for bug 1089908

Doesn't appear on already installed systems because the theme is hardcoded into Plank and written out only if no theme exists.

To update to latest theme, you have to remove ~/.config/plank/theme folder and restart Plank.

I recall there's a branch with more proper theming done by Rico; I'm sorry I didn't track the progress of this feature, that could have avoided such stalling.