incorrect boot sequence after update-manager reboot

[Humphrey van Polanen Petel]

I have a dual-boot system (WindowsXP-Ubuntu 12.04).
I have my boot manager set to remember the last choice.
I last selected Ubuntu from my boot sequence.
After rebooting via update-manager, the boot sequence selection was Windows rather than Ubuntu.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.11
ProcVersionSignature: Ubuntu 3.2.0-33.52-generic 3.2.31
Uname: Linux 3.2.0-33-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu15
Architecture: amd64
Date: Thu Nov 15 14:14:22 2012
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1352949223
 com.ubuntu.update-manager window-height 600
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
InterpreterPath: /usr/bin/python2.7
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_AU:en
 PATH=(custom, no user)
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to precise on 2012-05-01 (198 days ago)