CIS has problem with the game Flyff

The game Flyff works fine with it from a first look , but when you try minimize Flyff [mostly in window mode] CIS just doesn’t let you do anything - open another flyff window or even open your browser.
I know the problem is CIS because I had no problems with other anti viruses , and I just wanna keep using CIS [It rocks ;D ] so please solve that problem.