--- a/src/pyams_form/form.py	Thu Oct 08 09:15:08 2015 +0200
+++ b/src/pyams_form/form.py	Thu Oct 08 09:16:55 2015 +0200
@@ -26,6 +26,7 @@
 from pyams_i18n.interfaces import II18n
 from pyams_skin.interfaces import IDialog, ISkinnable, IContentTitle
 from pyams_template.interfaces import IContentTemplate, ILayoutTemplate
+from pyams_utils.interfaces import FORBIDDEN_PERMISSION
 from pyramid_chameleon.interfaces import IChameleonTranslate
 from z3c.form.interfaces import DISPLAY_MODE, IErrorViewSnippet
 from zope.publisher.interfaces.browser import IBrowserRequest
@@ -35,7 +36,6 @@
 from pyams_pagelet.interfaces import PageletCreatedEvent
 from pyams_skin.skin import apply_skin
 from pyams_utils.adapter import adapter_config, ContextRequestViewAdapter
-from pyams_utils.list import unique
 from pyams_utils.url import absolute_url
 from pyramid.decorator import reify
 from pyramid.events import subscriber
@@ -99,24 +99,26 @@
         else:
             return II18n(self.context).query_attribute('title', request=self.request)
 
-    def update(self):
+    def check_mode(self):
+        content = self.getContent()
         # check form permission to get form mode
-        if self.edit_permission and not self.request.has_permission(self.edit_permission, self.getContent()):
+        if self.edit_permission and not self.request.has_permission(self.edit_permission, content):
             self.mode = DISPLAY_MODE
         # check form mode based on context checker
         registry = self.request.registry
         permission = None
-        for content in unique((self.getContent(), self.context)):
-            checker = registry.queryMultiAdapter((content, self.request, self), IFormContextPermissionChecker)
-            if checker is None:
-                checker = registry.queryAdapter(content, IFormContextPermissionChecker)
-            if checker is not None:
-                permission = checker.edit_permission
-                break
-        if permission != self.edit_permission:
-            if (permission == 'system.forbidden') or \
-               not self.request.has_permission(permission, self.getContent()):
+        checker = registry.queryMultiAdapter((content, self.request, self), IFormContextPermissionChecker)
+        if checker is None:
+            checker = registry.queryAdapter(content, IFormContextPermissionChecker)
+        if checker is not None:
+            permission = checker.edit_permission
+        if permission and (permission != self.edit_permission):
+            if (permission == FORBIDDEN_PERMISSION) or not self.request.has_permission(permission, content):
                 self.mode = DISPLAY_MODE
+
+    def update(self):
+        # check form mode
+        self.check_mode()
         # update form and sub-forms
         [subform.update() for subform in self.subforms]
         [tabform.update() for tabform in self.tabforms]
@@ -319,6 +321,7 @@
         self.request.registry.notify(PageletCreatedEvent(self))
         data, errors = {}, ()
         for form in self.forms:
+            form.check_mode()
             form.updateWidgets()
             form.updateActions()
             form_data, form_errors = form.extractData()
@@ -354,7 +357,7 @@
 
     buttons = Buttons(Interface)
 
-    def __init__(self, context, request, view):
+    def __init__(self, context, request, view=None):
         super(InnerAddForm, self).__init__(context, request)
         self.parent_form = view
 
@@ -399,6 +402,7 @@
         self.request.registry.notify(PageletCreatedEvent(self))
         data, errors = {}, ()
         for form in self.forms:
+            form.check_mode()
             form.updateWidgets()
             form.updateActions()
             form_data, form_errors = form.extractData()
@@ -441,7 +445,7 @@
 
     buttons = Buttons(Interface)
 
-    def __init__(self, context, request, view):
+    def __init__(self, context, request, view=None):
         super(InnerEditForm, self).__init__(context, request)
         self.parent_form = view
 
@@ -477,7 +481,7 @@
 
     buttons = Buttons(Interface)
 
-    def __init__(self, context, request, view):
+    def __init__(self, context, request, view=None):
         super(InnerDisplayForm, self).__init__(context, request)
         self.parent_form = view