Firefox annoying problem

Hey guys,

I have an annoying Firefox problem that accrues now in the 3 version and on the previous 2.x versions. When I'm switching between tabs or when I'm clicking on some URL the browser often stuck and shows me the rainbow circle of the OSX. I have captured a video to show you but the capturing app didnt catch the rainbow circle (Imagine that it is...).

http://www.youtube.com/watch?v=9-fSf8pqu04

It happens a lot and it drive me crazy...

I have macbook 2.1 ghz with 2 GB ddr2.


What should i do???


Thanks,

Yuval