Clear xxx2many when there is no field for issue1708

tryton/gui/window/view_form/screen/screen.py

@@ -50,8 +50,7 @@ class Screen(SignalEvent):
         self.parent_name = None
         self.__window = window
         self.__group = None
-        self.group = Group(model_name, {}, self.window, context=self.context,
-                readonly=readonly)
+        self.new_group()
         self.__current_record = None
         self.current_record = None
         self.screen_container = ScreenContainer()
@@ -178,6 +177,10 @@ class Screen(SignalEvent):
 
     group = property(__get_group, __set_group)
 
+    def new_group(self, readonly=False):
+        self.group = Group(self.model_name, {}, self.window,
+                context=self.context, readonly=readonly)
+
     def _group_cleared(self, group, signal):
         for view in self.views:
             if hasattr(view, 'reload'):

tryton/gui/window/view_form/view/form_gtk/many2many.py

@@ -151,7 +151,9 @@ class Many2Many(WidgetInterface):
     def display(self, record, field):
         super(Many2Many, self).display(record, field)
         if field is None:
+            self.screen.new_group()
             self.screen.current_record = None
+            self.screen.parent = True
             self.screen.display()
             return False
         new_group = field.get_client(record)

tryton/gui/window/view_form/view/form_gtk/one2many.py

@@ -5,7 +5,6 @@ import gettext
 from tryton.common import TRYTON_ICON, COLOR_SCHEMES
 from interface import WidgetInterface
 from tryton.gui.window.view_form.screen import Screen
-from tryton.gui.window.view_form.model.group import Group
 from tryton.gui.window.win_search import WinSearch
 from tryton.gui.window.win_form import WinForm
 from tryton.gui.window.view_form.widget_search.form import _LIMIT
@@ -324,7 +323,9 @@ class One2Many(WidgetInterface):
     def display(self, record, field):
         super(One2Many, self).display(record, field)
         if field is None:
+            self.screen.new_group()
             self.screen.current_record = None
+            self.screen.parent = True
             self.screen.display()
             return False
         new_group = field.get_client(record)