Add a note about spam and the header cache in the manual.

diff --git a/doc/manual.xml.head b/doc/manual.xml.head
index 5ae3021f63f4cdabce26af22646bb793e6fec109..8b683e4563ca02bba6c303cbc9cbc95a6f39b705 100644 (file)
--- a/doc/manual.xml.head
+++ b/doc/manual.xml.head
@@ -4158,6 +4158,17 @@ linkend="index-format">$index_format</link> variable. (Tip: try
 defined for a given message.)
 </para>
 
+<para>
+Note: the value displayed by <literal>%H</literal> and searched by
+<literal>~H</literal> is stored in the <link linkend="caching">header
+cache</link>.  Mutt isn't smart enough to invalidate a header cache
+entry based on changing <literal>spam</literal> rules, so if you
+aren't seeing correct <literal>%H</literal> values, try temporarily
+turning off the header cache.  If that fixes the problem, then once
+your spam rules are set to your liking, remove your stale header cache
+files and turn the header cache back on.
+</para>
+
 <para>
 Your first step is to define your external filter's spam patterns using
 the <command>spam</command> command. <emphasis>pattern</emphasis> should