--- a/hgext/mq.py	Mon Nov 17 01:48:19 2014 +0100
+++ b/hgext/mq.py	Mon Nov 17 01:48:43 2014 +0100
@@ -151,6 +151,8 @@
     return lines
 
 def insertplainheader(lines, header, value):
+    if lines and lines[0] and ':' not in lines[0]:
+        lines.insert(0, '')
     lines.insert(0, '%s: %s' % (header, value))
     return lines