diff --git a/web_widget_x2many_2d_matrix/README.rst b/web_widget_x2many_2d_matrix/README.rst
index 85d5dd712..7861687f5 100644
--- a/web_widget_x2many_2d_matrix/README.rst
+++ b/web_widget_x2many_2d_matrix/README.rst
@@ -123,12 +123,15 @@ Known issues / Roadmap
 * If you pass values with an onchange, you need to overwrite the model's method
   `onchange` for making the widget work::
 
- @api.multi
- def onchange(self, values, field_name, field_onchange):
-     if "one2many_field" in field_onchange:
-         for sub in [<field_list>]:
-             field_onchange.setdefault("one2many_field." + sub, u"")
-     return super(model, self).onchange(values, field_name, field_onchange)
+ .. code-block:: python
+
+    @api.multi
+    def onchange(self, values, field_name, field_onchange):
+        if "one2many_field" in field_onchange:
+            for sub in [<field_list>]:
+                field_onchange.setdefault("one2many_field." + sub, u"")
+        return super(model, self).onchange(values, field_name, field_onchange)
+
 
 Bug Tracker
 ===========