Can't disable annoying pop-up windows in the upper right

Binary package hint: pidgin

Pidging now shows all incoming messages and event in a system popup notification window.
This is highly annoying. It's not possible to dismiss them manually. It's not possible to turn this off in preferences.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: pidgin 1:2.7.11-1ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Fri Jun 3 19:22:21 2011
ExecutablePath: /usr/bin/pidgin
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: pidgin
UpgradeStatus: Upgraded to natty on 2011-05-05 (28 days ago)