--- a/src/ztfy/myams/interfaces/__init__.py	Tue Oct 14 14:34:41 2014 +0200
+++ b/src/ztfy/myams/interfaces/__init__.py	Tue Oct 14 14:35:34 2014 +0200
@@ -7,6 +7,7 @@
 # import standard packages
 
 # import Zope3 interfaces
+from z3c.form.interfaces import IInputForm
 from ztfy.baseskin.interfaces import ISkinnable
 from ztfy.baseskin.interfaces.form import checkSubmitButton
 
@@ -89,3 +90,7 @@
     """Modal display form buttons"""
 
     close = CloseButton(name='close', title=_("Close"))
+
+
+class IInnerForm(IInputForm):
+    """Inner form marker interface"""