After upgradinng to 15.04 today, something is wrong with the Adwaita theme and I have boxes like this one all over the place:
Oddly, in the screenshot, it's a big white box, but on my system it shows up as a big black box (if I took a picture of my screen with a camera, the box that's white above would be black!)
Switching away from the Adwaita theme seems to fix the issue, but I have been using Adwaita for a long time and don't want to use another theme.
I reinstalled Adwaita:
sudo apt-get install --reinstall adwaita*
But that didn't help either.
Any ideas how to get the theme fixed?
EDIT: Here's another example, but it's actually black in this image: