diff --git a/tiramisu/setting.py b/tiramisu/setting.py
index a20f88a..d6537ef 100644
--- a/tiramisu/setting.py
+++ b/tiramisu/setting.py
@@ -32,7 +32,7 @@ ro_remove = ('permissive', 'hidden')
 ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen', 'mandatory')
 rw_remove = ('permissive', 'everything_frozen', 'mandatory')
 rw_append = ('frozen', 'disabled', 'validator', 'hidden')
-
+default_properties = set(('expire', 'validator'))
 
 class _const:
     """convenient class that emulates a module
@@ -182,7 +182,7 @@ class Setting(object):
     def __init__(self, context):
         # properties attribute: the name of a property enables this property
         # key is None for global properties
-        self._properties = {None: set(('expire', 'validator'))}
+        self._properties = {}
         # permissive properties
         self._permissives = {}
         # generic owner
@@ -204,9 +204,16 @@ class Setting(object):
     def __setitem__(self, opt, value):
         raise ValueError('you must only append/remove properties')
 
+    def reset(self):
+        try:
+            del(self._properties[None])
+        except KeyError:
+            pass
+        self.context.cfgimpl_reset_cache()
+
     def _get_properties(self, opt=None, is_apply_req=True):
         if opt is None:
-            props = self._properties.get(opt, set())
+            props = self._properties.get(opt, copy(default_properties))
         else:
             exp = None
             if opt in self._cache: