service-discovery-applet shows redundant services when multiple NICs active

Looking at the code, and I am neither a python expert nor a gtk expert, it appears that a suitable change can be made around line 320 in service-discovery-applet.

The code there is:

 menuitem = gtk.MenuItem(name, False)
 self.zc_types[type].add(menuitem)
 self.zc_services[(interface, protocol, name, type, domain)] = menuitem
 menuitem.connect("activate", self.menuitem_response,interface, protocol, name, type, domain)
 menuitem.show_all()

When we actually connect to a service, the code is:

      self.plugin.plugins[type][0].connect(self.use_host_names, name, type, host, address, port, txts)

with no use of the interface.

It seems to me that we should either modify the menu building code to filter out duplicates, or else put the interface name in the menu if someone thinks it will be significant (which it clearly is not at this time).

Agree. In DNS-SD, services are defined at the IP level by a host/port pair. Thus, the service will be accesed according to routing rules, and the interface info is of no use. So, if both interfaces are on the same network, only one entry should be shown.
Though, if both interfaces are on different networks, and both networks happen to have services named the same... Really improvable but I guess the plugin could check the services aren't the same (looking at the addresses), and then tag them with the interface.