diff --git a/doc/tiramisu.jpeg b/doc/tiramisu.jpeg
index 84b391d..0b5c4ae 100644
Binary files a/doc/tiramisu.jpeg and b/doc/tiramisu.jpeg differ
diff --git a/tiramisu/config.py b/tiramisu/config.py
index 553e9b7..4bec77e 100644
--- a/tiramisu/config.py
+++ b/tiramisu/config.py
@@ -96,19 +96,19 @@ class Config(object):
         except TypeError:
             pass
         else:
-            #if master/slave group, add default_multi value if length of valu
-            #if inferior to group length
+            #if master/slave group, add default_multi value if length of value
+            #is inferior of length's group
             for child in self._cfgimpl_descr._children:
-                value = self._cfgimpl_values[child._name]
-                if value is None:
-                    len_child = 0
-                    value = Multi([], config=self, opt=child, force_append=False)
-                else:
-                    len_child = len(value)
-                if len_child < max_len_child:
-                    for num in range(len_child, max_len_child):
-                        value._append_default()
-
+                if isinstance(child, Option):
+                    value = self._cfgimpl_values[child._name]
+                    if value is None:
+                        len_child = 0
+                        value = Multi([], config=self, opt=child, force_append=False)
+                    else:
+                        len_child = len(value)
+                    if len_child < max_len_child:
+                        for num in range(len_child, max_len_child):
+                            value._append_default()
 
     def cfgimpl_update(self):
         """dynamically adds `Option()` or `OptionDescription()`