The ebuild for dev-cpp/libgnomemm-2.26.0 appears to have gotten lost on the way to the deli. Versions 2.22.0 and 2.24.0 are present, whereas dev-cpp/libgnomeuimm is present in versions 2.22.0 and 2.26.0. Changelog talks about old versions getting removed, but I have libgnome-2.26.0 installed currently, but sans ebuild portage now wants to downgrade all the time of course. This indicates that this happened more or less recently.
Please resync and check again
(In reply to comment #1) > Please resync and check again Confirmed. Problem is gone now... Was persistent for some time now though. Maybe everybody else uses overlays for Gnome, or libgnomemm doesn't enjoy huge followership. :o)