If you're using Ubuntu 11.04 with the classic Ubuntu desktop (no Unity), you've probably noticed that not all Compiz plugins work as they used to in Ubuntu 10.10 and changing some of the default Compiz settings results in quite a few bugs. This can be solved by downgrading Compiz to version 0.8.6 (Compiz from Ubuntu 10.10).
Further more, downgrading Compiz will also give you the notification area (systray) back, without having to whitelist applications and without the bug that occurs sometimes when whitelisting the systray (which prevents you from clicking certain AppIndicators).
Warning: the instructions below are for the classic Ubuntu desktop session. This will remove Unity! Further more, this is experimental (and reverting the changes is a bit complicated and may not work exactly as described in this post) so use it at your own risk!
Downgrade Compiz to version 0.8.6 in Ubuntu 11.04
1. Log in to the classic Ubuntu desktop session (but I assume you already do this if you want to downgrade Compiz) and run the following commands to purge Compiz:
sudo apt-get purge compiz compiz-plugins-extra compiz-plugins-main
If you've installed CompizConfig Settings Manager, purge it too:
sudo apt-get purge compizconfig-settings-manager
If you've installed Emerald, also purge the following packages:
sudo apt-get purge libemeraldengine0 emerald
2. Add Giodic's PPA and install Compiz 0.8.6 (package versions changed so they won't be overwritten by the default Compiz in Natty):
sudo add-apt-repository ppa:guido-iodice/compiz-0.8.6-natty sudo apt-get update sudo apt-get upgrade sudo apt-get install compiz compiz-core compiz-fusion-plugins-main compiz-fusion-plugins-extra compiz-fusion-plugins-unsupported compiz-gnome compiz-plugins compizconfig-backend-gconf compizconfig-settings-manager libcompizconfig0 libdecoration0 python-compizconfig
3. Pinguy also provides a Compiz profile with the plugins enabled in Pinguy 10.10 which you can import if you want: download - then open CompizConfig Settings Manager and import this profile (in CompizConfig Settings Manager: Preferences > Import).
Revert the changes
If you want to revert the changes and use Compiz 0.9.4 again, run the commands below in a terminal:
sudo apt-get install ppa-purge sudo ppa-purge ppa:guido-iodice/compiz-0.8.6-natty sudo apt-get install -f sudo apt-get purge compiz-plugins-extra compiz-plugins-main compiz-fusion-plugins-unsupported sudo apt-get install ubuntu-desktop