Since the oneiric update, after some usage the dash and the launcher backgrounds (when open) become messy. Here you can see a screenshot:
Sometimes, I also noticed (don't know if it's a bug) that the dash shows the desktop behind, even if I have an application open. And also I noticed that when you change desktop background, the dash always shows the same background. This become evident when I use the wallpaper that change through the day.
Many thanks in advance!!
EDIT: I will report the bug for sure. Here you can see the "see-through" behaviour I was talking about. Is this a bug?