diff --git a/tiramisu_cmdline_parser.py b/tiramisu_cmdline_parser.py
index e4f8787..b4394ac 100644
--- a/tiramisu_cmdline_parser.py
+++ b/tiramisu_cmdline_parser.py
@@ -15,7 +15,7 @@
 
 
 from typing import Union, List, Optional
-from argparse import ArgumentParser, Namespace, SUPPRESS
+from argparse import ArgumentParser, Namespace, SUPPRESS, _HelpAction
 from tiramisu.error import PropertiesOptionError
 try:
     from tiramisu import Config
@@ -60,12 +60,30 @@ class TiramisuNamespace(Namespace):
         return super().__getattribute__(key)
 
 
+class _TiramisuHelpAction(_HelpAction):
+    needs = False
+    def __call__(self, *args, **kwargs):
+        _TiramisuHelpAction.needs = True
+
+    def display(self, parser):
+        _HelpAction.__call__(self, parser, None, None)
+
+
 class TiramisuCmdlineParser(ArgumentParser):
     def __init__(self,
                  *args,
+                 fullpath: bool=True,
                  **kwargs):
+        self.fullpath = fullpath
         self.config = None
         super().__init__(*args, **kwargs)
+        self.register('action', 'help', _TiramisuHelpAction)
+
+    def _pop_action_class(self, kwargs, default=None):
+        ret = super()._pop_action_class(kwargs, default)
+        if kwargs.get('action') != 'help' and kwargs.get('dest') != 'help':
+            return ret
+        return _TiramisuHelpAction
 
     def _match_arguments_partial(self,
                                  actions,
@@ -83,6 +101,24 @@ class TiramisuCmdlineParser(ArgumentParser):
             actions.pop(0)
         return super()._match_arguments_partial(actions, arg_string_pattern)
 
+    def _parse_known_args(self, args=None, namespace=None):
+
+        namespace_, args_ = super()._parse_known_args(args, namespace)
+        if args != args_ and args_ and args_[0].startswith(self.prefix_chars):
+            # option that was disabled are no more disable
+            # so create a new parser
+            new_parser = TiramisuCmdlineParser(self.prog, fullpath=self.fullpath)
+            new_parser._registries = self._registries
+            new_parser.add_arguments(self.config)
+            namespace_, args_ = new_parser._parse_known_args(args_, namespace)
+        else:
+            if self._registries['action']['help'].needs:
+                # display help only when all variables assignemnt are done
+                self._registries['action']['help'].needs = False
+                helper = self._registries['action']['help'](None)
+                helper.display(self)
+        return namespace_, args_
+
     def add_argument(self, *args, **kwargs):
         if args == ('-h', '--help'):
             super().add_argument(*args, **kwargs)
@@ -118,7 +154,8 @@ class TiramisuCmdlineParser(ArgumentParser):
                 raise ValueError('name cannot startswith "{}"'.format(self.prefix_chars))
             properties = obj.property.get()
             kwargs = {'help': option.doc().replace('%', '%%'),
-                      'default': SUPPRESS}
+                      'default': SUPPRESS,
+                      'dest': option.path()}
             if 'positional' in properties:
                 #if not 'mandatory' in properties:
                 #    raise ValueError('"positional" argument must be "mandatory" too')
@@ -126,7 +163,7 @@ class TiramisuCmdlineParser(ArgumentParser):
                 #if option.requires():
                 kwargs['nargs'] = '?'
             else:
-                if prefix:
+                if self.fullpath and prefix:
                     name = prefix + '.' + name
                 if len(name) == 1 and 'longargument' not in properties:
                     args = [self.prefix_chars + name]
@@ -199,20 +236,15 @@ class TiramisuCmdlineParser(ArgumentParser):
 
     def format_usage(self,
                      *args,
-                     _forhelp=False,
                      **kwargs):
-        if _forhelp:
-            return super().format_usage(*args, **kwargs)
-        help_formatter = TiramisuCmdlineParser(self.prog)
+        help_formatter = TiramisuCmdlineParser(self.prog, fullpath=self.fullpath)
         help_formatter.add_arguments(self.config, _forhelp=True)
-        return help_formatter.format_usage(*args, **kwargs, _forhelp=True)
+        return super(TiramisuCmdlineParser, help_formatter).format_usage(*args, **kwargs)
 
-    def format_help(self, *args, _forhelp=False, **kwargs):
-        if _forhelp:
-            return super().format_help(*args, **kwargs)
-        help_formatter = TiramisuCmdlineParser(self.prog)
+    def format_help(self, *args, **kwargs):
+        help_formatter = TiramisuCmdlineParser(self.prog, fullpath=self.fullpath)
         help_formatter.add_arguments(self.config, _forhelp=True)
-        return help_formatter.format_help(*args, **kwargs, _forhelp=True)
+        return super(TiramisuCmdlineParser, help_formatter).format_help(*args, **kwargs)
 
     def get_config(self):
         return self.config