slackbuilds_ponce/desktop/cairo-compmgr

cairo-compmgr (Drop-in replacement for xcompmgr)

This composite manager uses the cairo library to provide similar effects to
xcompmgr.  You can use it with any window manager, such as fluxbox, to
provide transparencies.  xcompmgr was designed as an example program and 
cairo-compmgr is designed as an actual standalone composite manager.

Warning: this plays a bit weird with fluxbox.  Tabs of grouped windows will
be drawn under windows if cycling through with alt+tab.  Additionally when a
sub sub root menu loops back over it self, it will be drawn under the other
menus.  Other than that, it's an added improvement in visual effects over
xcompmgr.

This requires vala.  libgtop, glade3, GConf, and gobject-introspection are
optional requirements, but gobject-introspection is not recommend since
upstream says support for it is still unstable.