gulle@gulle-desktop:~$ compiz
compiz (core) - Info: Loading plugin: core
compiz (core) - Info: Starting plugin: core
compiz (core) - Error: Screen 0 on display ":0.0" already has a window manager; try using the --replace option to replace the current window manager.
compiz (core) - Info: Stopping plugin: core
compiz (core) - Info: Unloading plugin: core
gulle@gulle-desktop:~$ xchat