cannot select menu items when scrolling

[avdd]

menu -> system -> preferences

panel on bottom with main menu

On my 1024x768 screen there are too many items to display. The menu allows scrolling but if I try to select the bottom items the menu jumps back to the top and i cannot select!

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: gnome-panel 1:2.30.2-0ubuntu0.2
ProcVersionSignature: Ubuntu 2.6.32-32.62-generic-pae 2.6.32.38+drm33.16
Uname: Linux 2.6.32-32-generic-pae i686
Architecture: i386
Date: Sun Jul 3 13:37:27 2011
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 10.04.2 LTS "Lucid Lynx" - Release i386 (20110211.1)
ProcEnviron:
 LC_COLLATE=C
 PATH=(custom, user)
 LANG=en_AU.utf8
 SHELL=/bin/bash
SourcePackage: gnome-panel