--- a/src/pyams_skin/interfaces/__init__.py	Thu May 03 12:39:11 2018 +0200
+++ b/src/pyams_skin/interfaces/__init__.py	Fri May 04 09:56:55 2018 +0200
@@ -60,6 +60,11 @@
                         required=True,
                         default=False)
 
+    no_inherit_skin = Bool(title=_("Don't inherit parent skin?"),
+                           description=_("Should we override parent skin?"),
+                           required=True,
+                           default=True)
+
     skin_parent = Attribute("Skin parent (local or inherited)")
 
     skin = Choice(title=_("Custom graphic theme"),
@@ -69,7 +74,7 @@
 
     @invariant
     def check_skin(self):
-        if not (self.skin or self.inherit_skin):
+        if self.no_inherit_skin and not self.skin:
             raise Invalid(_("You must select a custom skin or inherit from parent!"))
 
     def get_skin(self, request=None):