Window doesn't move from static workspace to a new dynamic one on dual-head

[achim]

Environment:
- Ubuntu 12.10 with gnome-shell (see below for version details)
- Nvidia 230M card with proprietary nvidia driver and twinview configuration
- Gnome-Shell with dual screen
- Primary screen on the right side
- Left screen is static

Reproduction:
- Enter window overview mode (via super key or hot corner)
- try to move a window (e.g. an evince instance) from the static workspace to a new workspace with the mouse
(NOT on an existing workspace i.e. between two to workspace to create a new one for that window)

Expected:
A new workspace is created and the window is put there

Actual behavior:
window moves back to the static screen -> no changes

##Gnome-Shell##
gnome-shell:
  Installed: 3.6.1-0ubuntu1.1
  Candidate: 3.6.1-0ubuntu1.1
  Version table:
 *** 3.6.1-0ubuntu1.1 0
        500 http://de.archive.ubuntu.com/ubuntu/ quantal-updates/universe amd64 Packages
        100 /var/lib/dpkg/status
     3.6.1-0ubuntu1 0
        500 http://de.archive.ubuntu.com/ubuntu/ quantal/universe amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gnome-shell 3.6.1-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Sun Nov 25 15:18:00 2012
DisplayManager: lightdm
GsettingsChanges:
 b'org.gnome.desktop.interface' b'clock-show-date' b'true'
 b'org.gnome.desktop.interface' b'cursor-theme' b"'DMZ-Black'"
InstallationDate: Installed on 2012-11-23 (1 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 12.10 (quantal) reached end-of-life on May 16, 2014.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test.

[Launchpad Janitor (janitor)]

[Expired for gnome-shell (Ubuntu) because there has been no activity for 60 days.]