I have a very strange issue with my R.A.T. 9 wireless mouse. When I plug it in, I can scroll and click etc, but I can't change window focus! Whenever I click on a window, it stays unfocused. This issue disappears as soon as unplug the receiver. Nothing obvious in dmesg. dmesg shows when I plugged in the receiver, when I unplugged my second mouse, and finally, when I plugged in my second mouse again, and when I unplugged the receiver. No errors around those times at all.

What other debug info should I provide?

Ubuntu 12.04 64 bit.