I cannot type in a message with koi8. An attempt to change encoding does not change the font.

Binary package hint: thunderbird

It appeared when I switched from xfce to gnome, but acts even when I work under xfce.
I came accross this ugly behavior of thunderbird and other programs like gvim under gnome
several times, under debian.

I just want to be able to use any font, whatever I like at the moment, which is installed on the system. I feel deeply insulted when the system pretends to know better which fonts are
to be used.

This is Ubuntu 7.10,
"apt-cache policy thunderbird" gives the following message:
 Installed: 2.0.0.8~pre071022+nobinonly-0ubuntu0.7.10
  Candidate: 2.0.0.12+nobinonly-0ubuntu0.7.10.0
  Version table:
     2.0.0.12+nobinonly-0ubuntu0.7.10.0 0
        500 http://us.archive.ubuntu.com gutsy-updates/main Packages
        500 http://security.ubuntu.com gutsy-security/main Packages
 *** 2.0.0.8~pre071022+nobinonly-0ubuntu0.7.10 0
        100 /var/lib/dpkg/status
     2.0.0.6+nobinonly-0ubuntu1 0
        500 http://us.archive.ubuntu.com gutsy/main Packages

I expect that when composing message I chose koi8r encoding and type in
using koi8r keybord, I would see cyrillic letters, but instead I see something like this:
 ÆÙ×ÁÐ.

ProblemType: Bug
Architecture: i386
Date: Mon Mar 24 15:46:05 2008
DistroRelease: Ubuntu 7.10
Package: mozilla-thunderbird 2.0.0.8~pre071022+nobinonly-0ubuntu0.7.10
PackageArchitecture: all
SourcePackage: thunderbird
Uname: Linux fujiboo 2.6.22-14-generic #1 SMP Fri Feb 1 04:59:50 UTC 2008 i686 GNU/Linux