I have the same problem, so I reflashed rootfs and emmc. One by one I will load up new software, and see what could have caused it. I'm leaning towards a tweak in N9 Quicktweak, inception, or unrestricted system-ui. I had just reflashed a week ago, and the above is all that I installed, so I'm sure I could find the problem.
Thank you very much, worked although I had to do chmod -R 775 /usr/share/icons/hicolor/ .