diff --git a/addons/web/static/src/js/views/form_relational_widgets.js b/addons/web/static/src/js/views/form_relational_widgets.js
index dd4c4fb0fb671..00640696b4181 100644
--- a/addons/web/static/src/js/views/form_relational_widgets.js
+++ b/addons/web/static/src/js/views/form_relational_widgets.js
@@ -1275,6 +1275,9 @@ var FieldOne2Many = FieldX2Many.extend({
             return self.mutex.def;
         });
     },
+    is_false: function() {
+        return false;
+    },
 });
 
 var Many2ManyListView = X2ManyListView.extend({