Como root, edite o arquivo /etc/sysconfig/compositing-wm e coloque como mostrado abaixo:
# COMPOSITING_WM_START values:
# yes: start compositing window manager on session start
# auto: start compositing window manager on session start
# if Xgl is started
# or if direct rendering and GLX_EXT_texture_from_pixmap are available
# no: do not start compositing window manager on session start
COMPOSITING_WM_START=no
# if COMPOSITING_WM is not empty, it overrides the default compositing
# window manager (which is compiz)
COMPOSITING_WM=
# if COMPOSITING_WM_ARGS is defined, it is used as
# arguments for the compositing window manager
#COMPOSITING_WM_ARGS=
# if COMPOSITING_WINDOW_DECORATOR is defined, it overrides the default
# window decorator, the specified program will be run after
# compositing window manager
# NB When using compiz fusion the decorator is started automatically.
#COMPOSITING_WINDOW_DECORATOR=