I found this instructions how to solve problem with weird pink shadow on ubuntu forums. 

Instructions :

- Open a terminal window.

- Type: sudo rm /usr/lib/xorg/modules/libwfb.so

- Then type: sudo ln -s /usr/lib/nvidia/libwfb.so.xserver-xorg-core /usr/lib/xorg/modules/libwfb.so

- Restart X (either reboot or “Alt-Ctrl-Backspace”)

 Enjoy well working compiz. ;)