I’m running Vista in a VirtualBox virtual machine that I have installed on Ubuntu 8.04. This all worked great until I recently enabled the support to enter complex characters in order to be able to test how some software behaves when using an IME. This morning when I started my virtual machine, it didn’t respond to any keyboard input.
Enabling the complex character support installed SCIM. A quick Google search revealed a nice solution for the problem: unsetting the variables QT_IM_MODULE, XMODIFIERS, and GTK_IM_MODULE before you start VirtualBox prevents VirtualBox from communicating with Scim (which is what I want anyways since the VM itself might have its own IMEs).
Since I usually start VirtualBox from a launcher in the panel, I opened the properties of the VirtualBox launcher and replaced the command with
/bin/bash -c "unset QT_IM_MODULE && unset XMODIFIERS && unset GTK_IM_MODULE && virtualbox"
Now keyboard input again works!