prevent tracebacks

src/groupchat_control.py

@@ -2518,7 +2518,7 @@ class GroupchatControl(ChatControlBase):
         elif event.button == 2: # middle click
             widget.get_selection().select_path(path)
             iter_ = self.model.get_iter(path)
-            if len(path) == 2:
+            if path.get_depth() == 2:
                 nick = self.model[iter_][C_NICK]
                 self._start_private_message(nick)
             return True

src/roster_window.py

@@ -4503,7 +4503,7 @@ class RosterWindow:
             return
         path = list_of_paths[0]
         data = ''
-        if len(path) >= 2:
+        if path.get_depth() >= 2:
             data = model[path][C_JID]
         selection.set(selection.target, 8, data)