I'm seeing the mouse pointer flickers and disappears when moving the mouse pointer over icons in the main system settings dialog.
Also the mouse seems to generally flicker in all sorts of places like buttons in all applications.
Tested this using a Ubuntu 11.10 LiveCD guest with Unity 2D under VirtualBox 4.1.4 (Windows 7 Host) Guest Additions not installed.
VirtualBox 4.1.4 gives the guest a tablet device instead of a regular mouse before installing the guest additions. this allows VirtualBox to support "mouse pointer integration" before installing the guest additions.
The bug might be caused by problematic handling of Tablet devices in Ubuntu.
ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: gnome-settings-daemon 3.2.0-0ubuntu5
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
CasperVersion: 1.287
Date: Thu Oct 13 22:13:24 2011
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: gnome-settings-daemon
UpgradeStatus: No upgrade log present (probably fresh install)
EOL have been reached, so no more maintenance. If that issue still exist, then report again using ubuntu-bug.