If this option is set, then a message-list specifier in the form ``/x:y''
will expand to all messages containing the substring ``y'' in the header
field ``x''. The string search is case insensitive.
If this option is set, then a message-list specifier in the form ``/x:y''
will expand to all messages containing the substring ``y'' in the header
field ``x''. The string search is case insensitive.
-The form ``/To:y'' is a special case, and will expand
+If ``x'' is ommitted, it will default to the ``Subject'' header field.
+The form ``/to:y'' is a special case, and will expand
to all messages containing the substring ``y'' in the ``To'', ``Cc''
or ``Bcc'' header fields.
to all messages containing the substring ``y'' in the ``To'', ``Cc''
or ``Bcc'' header fields.