VirtualBox Client screen resolution

I was testing the VirtualBox (with USB support) version, and notice something different from the previous version (or some discrete incompactibility to the new Ubuntu 9.10). Even if you install the Guest Additions, the VirtualBox does not allow you to increase the default screen size (800×600). I found the solution for this here, but for my own reference, I will leave the code posted here too:

Just close the current VirtualBox, and from the terminal (command-line), you just type:

# the resolution should be the maximum supported by the host screen
user@localhost:~$ VBoxManage setextradata global GUI/MaxGuestResolution 1280,800

And once you restart VirtualBox, you may then increase the screen resolution on the client machine.