network dialog: show only populated chains

gui/qt/network_dialog.py

@@ -98,12 +98,13 @@ class NodesListWidget(QTreeWidget):
         n_chains = len(network.blockchains)
         if n_chains > 1:
             for b in network.blockchains.values():
+                items = filter(lambda i: i.blockchain==b, network.interfaces.values())
+                if items:
                     name = network.get_blockchain_name(b)
                     x = QTreeWidgetItem([name + '@%d'%checkpoint, '%d'%b.height()])
                     x.setData(0, Qt.UserRole, 1)
                     x.setData(1, Qt.UserRole, b.checkpoint)
-                for i in network.interfaces.values():
+                    for i in items:
-                    if i.blockchain == b:
                         star = ' *' if i == network.interface else ''
                         item = QTreeWidgetItem([i.host + star, '%d'%i.tip])
                         item.setData(0, Qt.UserRole, 0)