Genie effect slows down

Hi,

I have noticed that Genie effect (minimizing effect) starts to lag, and become slow, after I have run certain applications.

These applications include: Mozilla Thunderbird, Mozilla Firefox, and Skype.

I have noticed that while I stay away from these apps, my genie effect is smooth as it should be.

However, it seems that after I have run some of these apps for a while, Genie effect slows down. And it stays slow even if I quit the apps. Actually, it is not slow, but rather it LAGS, meaning like the framerate is not good, or it is NOT SMOOTH. So slow is not the correct word.

I can't fix this slowiness unless I restart, or go to activity monitor and Force Quit windowserver (which really restarts everything I was doing).

What could be causing this??

(btw, it's not only these three apps. If I recall correctly, there was some alarm clock app a I tried a while back that caused this as well)

Somone help me please.

And I promise you: I have many times formatted my computer from scratch, and reinstalled mac os x. This doesn't fix anything.

Regards,
D