tryton client crashes when hitting close button
latest of 3.4 branch
1. Create internal shipment
2. Assign
3. Get failed to assign window
4. Close the window with "X"
5. Exception
ERROR:tryton.common.common: File "local/lib/python2.7/site-packages/tryton/common/common.py", line 1337, in process
self.callback(return_)
File "local/lib/python2.7/site-packages/tryton/gui/window/wizard.py", line 364, in end_callback
self.destroy(action=action())
File "local/lib/python2.7/site-packages/tryton/gui/window/wizard.py", line 334, in destroy
super(WizardDialog, self).destroy()
File "local/lib/python2.7/site-packages/tryton/gui/window/wizard.py", line 123, in destroy
self.screen.destroy()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/screen/screen.py", line 326, in destroy
self.group.destroy()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/model/group.py", line 425, in destroy
self.clear()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/model/group.py", line 128, in clear
record.destroy()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/model/record.py", line 630, in destroy
v.destroy()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/model/group.py", line 425, in destroy
self.clear()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/model/group.py", line 127, in clear
self.signal('group-list-changed', ('record-removed', record))
File "local/lib/python2.7/site-packages/tryton/signal_event.py", line 14, in signal
fnct(self, signal_data, *data)
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/screen/screen.py", line 278, in _group_list_changed
view.group_list_changed(group, signal)
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/view/list.py", line 948, in group_list_changed
self.display()
File "local/lib/python2.7/site-packages/tryton/gui/window/view_form/view/list.py", line 1073, in display
selection.select_path(path)
'NoneType' object has no attribute 'select_path'