[ubuntu] Virtualbox screen resolution 1920x1080 disappeared from the list

Hi,

I am running Ubuntu 12.10 and Virtualbox 4.1.18.

I have a VM guest running Windows 7 64 and it was working fine at 1920x1080 screen resolution.

This morning I was playing with the other resolutions at the guest window and suddenly I couldn't go back to the 1920x1080 anymore because it disappeared from the list.

I tried to reboot either the guest as well the host but the 1920x1080 resolution seems to be gone forever.

Any idea about what may happened? Any possible solution without to have to reinstall the whole stuff?

Thanks!