gnome-shell got memory leaks ?

[邓尧 <torshie gmail com>]

I'm using gnome-shell 3.4.1 under ubuntu 12.04 64-bit, ubuntu official binaries.
Right after logging in, "top" utility shows that gnome-shell consumes about 1.3G memory. IMO, 1.3G for a window manager is a lot, but still acceptable. After using for about two hours, its memory consumption grows up to more than 2.5G, and keeps growing! Smells like memory leaks :-(
I'm using nvidia 295.40 driver.
Anyone how to fix this ?

Thanks
Yao