I enabled the proposed repository in a fresh install with the proprietary
nvidia-173 driver. After the reboot, I noticed that minimizing and maximizing, there were none of the expected effect (using Ubuntu Classic, even with proprietary driver, Unity does not work - another issue). Furthermore I confirmed by trying to switch workspaces using keyboard shortcuts, and the square desktop wall was replaced by horizontally lined workspaces of Metacity.
Of course, the upgraded Compiz could be responsible, but I can't figure out what to do - please advice. Additionally, if it's an issue with the softwares from proposed repo, how and what do I do to notify the developers of the issue?