System tray notification icon is very annoying and not useful

Binary package hint: kpackagekit

Every few minutes, a notification icon pops up, just for a few seconds. Looks like it only checks for updates, and doesn't actually notify me of anything - but it is annoying because when it appears, it causes other icons to move, the taskbar to change size, and so on. I can't close it because it disappears too soon, and I can't find a way to disable it.
It looks like it is created by /usr/lib/kde4/libexec/kpackagekitsmarticon.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: kpackagekit 0.6.3.3-0ubuntu2
Uname: Linux 2.6.39 x86_64
Architecture: amd64
Date: Mon Jun 20 12:58:30 2011
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: kpackagekit
UpgradeStatus: Upgraded to natty on 2011-04-30 (51 days ago)