GtkImage seems to be missing GtkPixmap's "insensitive" feature

[Darin Adler <darin bentspoon com>]

I noticed that the toolbar buttons in Nautilus don't gray out when they are
not sensitive. Bonobo creates a GtkImage inside a Gtk[VH]Box inside a
GtkButton inside a BonoboUIToolbarButtonItem.

I tracked it down to this underlying issue; in the old days GtkPixmap
objects automatically changed to a grayed-out appearance when insensitive.
What's the intent here for gtk 2? Which level should implement the desired
"faded" look for insensitive toolbar buttons?

    -- Darin