I use FVWM windows manager (and I don't have gnome/unity installed). The background colour of my window is set by Ubuntu - it is the same colour as the background to the login screen. Indeed, the FVWM faqs notes that:
Setting the background image is not really part of the window
manager. If you are using one of the Linux distributions, most
likely, some part of the distribution is setting the background for
you.
In previous versions (10.04) this background colour was a tasteful brown, but now in 11.10 it is an unbearable blue. How do I change it please?