[Multi Monitor] Window entry jumps from right panel to left panel when it's minimized and back when restored again

[peter mueller]

As described in the summary:
1. Open any window and put it on the right (main monitor) in a Nvidia twinview setup.
2. Minimize said window
-> Effect: The window entry on the taskbar will jump to the left monitor. Once you click to restore the minimized window, it will visibly restore to the upper/left corner of the left screen (I assume that this is the [0,0]-coordinates) and then jump to the original position on the right monitor.
I have created some screenshots before/after minimizing some windows, using Ubu12.04 with gnome classic + effects. The screenshots can be found here: https://imgur.com/a/zk0gl
For ease of use direct links:
First 2 open windows. The entries are on the correct (right) monitor, where the windows reside: http://i.imgur.com/ZhWtH.png
Then minimized: the window entries jump to the left window list: http://i.imgur.com/2mykn.png

What should happen is, the window minimizes and the entry in the task list stays on that monitor.

This bug can be observed using the latest version of Ubuntu 12.04 using gnome-classic with effects. Alternatively, this can also be observed using the latest version of Xubuntu 12.04 with compiz running and replacing xfwm4.

Compiz version:
compiz:
  Installed: 1:0.9.7.6-0ubuntu1
  Candidate: 1:0.9.7.6-0ubuntu1
  Version table:
 *** 1:0.9.7.6-0ubuntu1 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

[peter mueller (grandmastermt2000)]

Activating "Keep previews of minimized windows" in CCSM @ "Workarounds" fixes this. (Tested on Ubuntu 12.04. I have yet to test Xubuntu 12.04 with Compiz)

[Launchpad Janitor (janitor)]

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