--- a/hgext/patchbomb.py	Tue Nov 25 22:52:25 2008 +0100
+++ b/hgext/patchbomb.py	Tue Nov 25 23:13:14 2008 +0100
@@ -402,6 +402,7 @@
             m['Message-Id'] = genmsgid('patchbomb')
         if parent:
             m['In-Reply-To'] = parent
+            m['References'] = parent
         else:
             parent = m['Message-Id']
         m['Date'] = util.datestr(start_time, "%a, %d %b %Y %H:%M:%S %1%2")