diff --git a/tryton/gui/window/view_form/view/form_gtk/many2many.py b/tryton/gui/window/view_form/view/form_gtk/many2many.py
index 00766107a0..7e66d786b6 100644
--- a/tryton/gui/window/view_form/view/form_gtk/many2many.py
+++ b/tryton/gui/window/view_form/view/form_gtk/many2many.py
@@ -223,7 +223,7 @@ class Many2Many(WidgetInterface):
         if field is None:
             self.screen.new_group()
             self.screen.current_record = None
-            self.screen.parent = None
+            self.screen.parent = True
             self.screen.display()
             return False
         new_group = field.get_client(record)
diff --git a/tryton/gui/window/view_form/view/form_gtk/one2many.py b/tryton/gui/window/view_form/view/form_gtk/one2many.py
index 4c4bf66128..3964488220 100644
--- a/tryton/gui/window/view_form/view/form_gtk/one2many.py
+++ b/tryton/gui/window/view_form/view/form_gtk/one2many.py
@@ -441,7 +441,7 @@ class One2Many(WidgetInterface):
         if field is None:
             self.screen.new_group()
             self.screen.current_record = None
-            self.screen.parent = None
+            self.screen.parent = True
             self.screen.display()
             return False
         new_group = field.get_client(record)