After check for updates complete, packages in list dissappear and reappear (sometimes one by one)

[Greg A]

Steps to reproduce:

1. Get Update Manager to a state when there are updates available, and visible in the list
2. Press Check

Expected result: previous packages stay on list, new available packages are added to the list, any now unavailable packages are removed from the list.

Actual result: entire list disappears and is slowly repopulated (even if nothing has changed)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.10
ProcVersionSignature: Ubuntu 3.2.0-22.35-generic 3.2.14
Uname: Linux 3.2.0-22-generic x86_64
ApportVersion: 2.0.1-0ubuntu2
Architecture: amd64
Date: Thu Apr 12 16:00:31 2012
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1334242751
 com.ubuntu.update-manager show-details true
 com.ubuntu.update-manager window-height 972
 com.ubuntu.update-manager window-width 640
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120112)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.