Comment 8 for bug 588609

When I try to install xubuntu-desktop via Synaptic, it tells me it will uninstall ubuntu-desktop and libsdl1.2debian-pulseaudio, so I guess that is due to the bugs you mention.

Anyway, if Charlie's affirmation ( "If more than one desktop meta-package is installed when attempting to upgrade using 'updte-manager', the upgrade will fail.") is correct, we should always leave only one xxx-desktop !!! (e.g. the last one)