Problems in running gnome3 environment on top of virtual box

[yinglcs]

Hi,

My host is Windows7 and I am using VirtualBox 4.1.4.

I have installed OS guests like:
Ubuntu 11.10 or Fedora 16 beta, both of which are configured to use Gnome 3 environment.

I have enabled 3d acceleration under VirtualBox for my OS guests.

But when I run Gnome 3, the text of part tool bar is missing. And some other times, it looks perfectly fine.

Has anyone else run into the same problem?
If yes, does anyone has a solution?

Thank you.