diff --git a/bin/osv/orm.py b/bin/osv/orm.py
index 0ccc022a925..7b7d9867240 100644
--- a/bin/osv/orm.py
+++ b/bin/osv/orm.py
@@ -792,6 +792,12 @@ class orm_template(object):
             result = self.view_header_get(cr, user, False, node.localName, context)
             if result:
                 node.setAttribute('string', result.decode('utf-8'))
+
+        elif node.nodeType==node.ELEMENT_NODE and node.localName == 'calendar':
+            for additional_field in ('date_start', 'date_delay', 'date_stop', 'color'):
+                if node.hasAttribute(additional_field) and node.getAttribute(additional_field):
+                    fields[node.getAttribute(additional_field)] = {}
+
         if node.nodeType == node.ELEMENT_NODE and node.hasAttribute('groups'):
             if node.getAttribute('groups'):
                 groups = node.getAttribute('groups').split(',')