--- a/src/pyams_form/group.py	Fri Jan 26 17:27:06 2018 +0100
+++ b/src/pyams_form/group.py	Fri Jan 26 17:27:31 2018 +0100
@@ -153,7 +153,7 @@
     def add_group(self, group):
         self._groups.append(group)
 
-    @property
+    @reify
     def groups(self):
         result = self._groups[:]
         others = []