Anyway, back to the main topic. Few hours ago Oracle released an update to their Virtualbox app which makes it now the 4.0.8, version. And if you use GNU/Linux Virtualisation with Virtualbox, then it is recommended to update to this latest version, according to the official Oracle changelog.
|Running MS Windows XP in a GNU/Linux desktop!...|
As you can see in the "list", not just improved stability and security fixes but it seems to include few Gnome 3/Shell and Ubuntu 11.04 related compability issues as well.
If you use Ubuntu 11.04 Natty Narwhal, then you can install Virtualbox 4.0.8 by issuing the below command and follow the instructions on your screen.
echo "deb http://download.virtualbox.org/virtualbox/debian $(lsb_release -sc) contrib" | sudo tee -a /etc/apt/sources.list
wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -
sudo apt-get update
sudo apt-get install virtualbox-4.0