I am having a problem where there is a white square that is visible across every icon. I have attached a snapshot to show the problem.

This problem arose while I was using Gnome Shell and the Faience theme. I am using 12.10, and have tried resetting the desktop to default unity and gnome 3 settings but it did not help. 

![enter image description here](https://i.stack.imgur.com/lZQu1.jpg)