mike@mike-desktop:~$ gtk-window-decorator --replace &
[1] 10215
mike@mike-desktop:~$
(gtk-window-decorator:10215): Gdk-WARNING **: Using Cairo rendering requires the drawable argument to
have a specified colormap. All windows have a colormap,
however, pixmaps only have colormap by default if they
were created with a non-NULL window argument. Otherwise
a colormap must be set on them with gdk_drawable_set_colormap

(gtk-window-decorator:10215): Gdk-CRITICAL **: gdk_cairo_create: assertion `GDK_IS_DRAWABLE (drawable)' failed