Comment 9 for bug 437532

There is no need for separate trays.
There is a fixed slots for system service in gnome-shell and , There already is a bug and patch upstream for gnome-panel > https://bugzilla.gnome.org/show_bug.cgi?id=583115
Maybe nautilus progress-info and the policky kit icons also should also get a slot.

Those interested in this bug could bring this up in the upstream gnome-panel bug..