remote deluged instance with bad connectivity causes "<type 'exceptions.TypeError'>: 'gtk.TreeIter' object has no attribute '__getitem__'"

[krichter]

A remote deluged instance which is accessed in deluge-gtk causes

** (deluge:27663): WARNING **: Invalid borders specified for theme pixmap:
        /usr/share/themes/Breeze/gtk-2.0/../assets/line-h.png,
borders don't fit within the image
/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/torrentview.py:611: GtkWarning: IA__gtk_tree_model_filter_convert_iter_to_child_iter: assertion 'filter_iter->stamp == filter->priv->stamp' failed
  child_row = self.treeview.get_model().get_model().convert_iter_to_child_iter(child_row)
richter@richter-Lenovo-IdeaPad-Z500:~:10005> deluge-gtk
01:54:11.368 [ERROR   ][deluge.ui.hostlist                 :203 ] Error resolving host richtercloud.de to ip: Name or service not known
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py", line 490, in on_hostlist_selection_changed
    self._update_widget_buttons()
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py", line 223, in _update_widget_buttons
    log.error('Error resolving host %s to ip: %s', row[HOSTLIST_COL_HOST], ex.args[1])
TypeError: 'gtk.TreeIter' object has no attribute '__getitem__'
02:03:20.095 [ERROR   ][deluge.ui.hostlist                 :203 ] Error resolving host richtercloud.de to ip: Name or service not known
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py", line 490, in on_hostlist_selection_changed
    self._update_widget_buttons()
  File "/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py", line 223, in _update_widget_buttons
    log.error('Error resolving host %s to ip: %s', row[HOSTLIST_COL_HOST], ex.args[1])
TypeError: 'gtk.TreeIter' object has no attribute '__getitem__'
02:04:14.839 [ERROR   ][deluge.ui.hostlist                 :203 ] Error resolving host richtercloud.de to ip: Name or service not known
Unhandled error in Deferred:
02:27:24.266 [CRITICAL][twisted                            :154 ] Unhandled error in Deferred:

02:27:24.266 [CRITICAL][deluge.log                         :93  ] twisted.internet.defer 
[Failure instance: Traceback: <type 'exceptions.TypeError'>: 'gtk.TreeIter' object has no attribute '__getitem__'
/usr/lib/python2.7/dist-packages/twisted/internet/defer.py:651:_runCallbacks
/usr/lib/python2.7/dist-packages/deluge/ui/client.py:381:__on_connect_fail
/usr/lib/python2.7/dist-packages/twisted/internet/defer.py:498:errback
/usr/lib/python2.7/dist-packages/twisted/internet/defer.py:565:_startRunCallbacks
--- <exception caught here> ---
/usr/lib/python2.7/dist-packages/twisted/internet/defer.py:651:_runCallbacks
/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py:184:on_host_status
/usr/lib/python2.7/dist-packages/deluge/ui/gtkui/connectionmanager.py:223:_update_widget_buttons
]

during the connection attempts as long as the connection dialog is open which results in the crash of a deluge-gtk process which seems to be a child process because the UI still remains visible, but only sometimes functional. The apport dialog on Ubuntu pops up and suggests to report a bug (which doesn't make sense because it's a PPA version).

experienced with 2.0.0.dev7097 on Ubuntu 17.04