Traceback (most recent call last): File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 863, in on_edit_clicked if dialog.run() == Gtk.ResponseType.OK: File "/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogEdit.py", line 123, in run index = self.sourceslist.list.index(self.source_entry) ValueError: is not in list