diff -U 8 -r mutt-1.5.21/OPS mutt-1.5.21-with-x-label/OPS
--- mutt-1.5.21/OPS	2010-03-01 09:56:19.000000000 -0800
+++ mutt-1.5.21-with-x-label/OPS	2011-12-12 15:53:47.000000000 -0800
@@ -51,16 +51,17 @@
 OP_DECODE_SAVE "make decoded copy (text/plain) and delete"
 OP_DELETE "delete the current entry"
 OP_DELETE_MAILBOX "delete the current mailbox (IMAP only)"
 OP_DELETE_SUBTHREAD "delete all messages in subthread"
 OP_DELETE_THREAD "delete all messages in thread"
 OP_DISPLAY_ADDRESS "display full address of sender"
 OP_DISPLAY_HEADERS "display message and toggle header weeding"
 OP_DISPLAY_MESSAGE "display a message"
+OP_EDIT_LABEL "add, change, or delete a message's label"
 OP_EDIT_MESSAGE "edit the raw message"
 OP_EDITOR_BACKSPACE "delete the char in front of the cursor"
 OP_EDITOR_BACKWARD_CHAR "move the cursor one character to the left"
 OP_EDITOR_BACKWARD_WORD "move the cursor to the beginning of the word"
 OP_EDITOR_BOL "jump to the beginning of the line"
 OP_EDITOR_BUFFY_CYCLE "cycle among incoming mailboxes"
 OP_EDITOR_COMPLETE "complete filename or alias"
 OP_EDITOR_COMPLETE_QUERY "complete address with query"
diff -U 8 -r mutt-1.5.21/PATCHES mutt-1.5.21-with-x-label/PATCHES
--- mutt-1.5.21/PATCHES	2008-03-19 13:07:06.000000000 -0700
+++ mutt-1.5.21-with-x-label/PATCHES	2011-12-12 15:53:47.000000000 -0800
@@ -0,0 +1 @@
+dgc.xlabel_ext.5
diff -U 8 -r mutt-1.5.21/copy.c mutt-1.5.21-with-x-label/copy.c
--- mutt-1.5.21/copy.c	2010-03-02 11:15:00.000000000 -0800
+++ mutt-1.5.21-with-x-label/copy.c	2011-12-12 15:53:47.000000000 -0800
@@ -106,16 +106,20 @@
 	    ascii_strncasecmp ("References:", buf, 11) == 0)
 	  continue;
 	if ((flags & CH_UPDATE_IRT) &&
 	    ascii_strncasecmp ("In-Reply-To:", buf, 12) == 0)
 	  continue;
 	ignore = 0;
       }
 
+      if (flags & CH_UPDATE_LABEL &&
+         mutt_strncasecmp ("X-Label:", buf, 8) == 0)
+        continue;
+
       if (!ignore && fputs (buf, out) == EOF)
 	return (-1);
     }
     return 0;
   }
 
   hdr_count = 1;
   x = 0;
@@ -407,16 +411,24 @@
   if (flags & CH_UPDATE_LEN &&
       (flags & CH_NOLEN) == 0)
   {
     fprintf (out, "Content-Length: " OFF_T_FMT "\n", h->content->length);
     if (h->lines != 0 || h->content->length == 0)
       fprintf (out, "Lines: %d\n", h->lines);
   }
 
+  if (flags & CH_UPDATE_LABEL && h->xlabel_changed)
+  {
+    if (h->env->x_label != NULL)
+      if (fprintf(out, "X-Label: %s\n", h->env->x_label) !=
+		  10 + strlen(h->env->x_label))
+        return -1;
+  }
+
   if ((flags & CH_NONEWLINE) == 0)
   {
     if (flags & CH_PREFIX)
       fputs(prefix, out);
     fputc ('\n', out); /* add header terminator */
   }
 
   if (ferror (out) || feof (out))
@@ -487,16 +499,19 @@
   if (flags & M_CM_PREFIX)
   {
     if (option (OPTTEXTFLOWED))
       strfcpy (prefix, ">", sizeof (prefix));
     else
       _mutt_make_string (prefix, sizeof (prefix), NONULL (Prefix), Context, hdr, 0);
   }
 
+  if (hdr->xlabel_changed)
+    chflags |= CH_UPDATE_LABEL;
+
   if ((flags & M_CM_NOHEADER) == 0)
   {
     if (flags & M_CM_PREFIX)
       chflags |= CH_PREFIX;
 
     else if (hdr->attach_del && (chflags & CH_UPDATE_LEN))
     {
       int new_lines;
diff -U 8 -r mutt-1.5.21/copy.h mutt-1.5.21-with-x-label/copy.h
--- mutt-1.5.21/copy.h	2009-08-25 12:08:52.000000000 -0700
+++ mutt-1.5.21-with-x-label/copy.h	2011-12-12 15:53:47.000000000 -0800
@@ -36,16 +36,18 @@
 /* flags for mutt_copy_header() */
 #define CH_UPDATE         1       /* update the status and x-status fields? */
 #define CH_WEED           (1<<1)  /* weed the headers? */
 #define CH_DECODE         (1<<2)  /* do RFC1522 decoding? */
 #define CH_XMIT           (1<<3)  /* transmitting this message? */
 #define CH_FROM           (1<<4)  /* retain the "From " message separator? */
 #define CH_PREFIX         (1<<5)  /* use Prefix string? */
 #define CH_NOSTATUS       (1<<6)  /* suppress the status and x-status fields */
+/* this absurd location to avoid conflict with cd.edit_threads -- *sigh* */
+#define CH_UPDATE_LABEL   (1<<20) /* update X-Label: from hdr->env->x_label? */
 #define CH_REORDER        (1<<7)  /* Re-order output of headers */
 #define CH_NONEWLINE      (1<<8)  /* don't output terminating newline */
 #define CH_MIME           (1<<9)  /* ignore MIME fields */
 #define CH_UPDATE_LEN     (1<<10) /* update Lines: and Content-Length: */
 #define CH_TXTPLAIN       (1<<11) /* generate text/plain MIME headers */
 #define CH_NOLEN          (1<<12) /* don't write Content-Length: and Lines: */
 #define CH_WEED_DELIVERED (1<<13) /* weed eventual Delivered-To headers */
 #define CH_FORCE_FROM     (1<<14) /* give CH_FROM precedence over CH_WEED? */
diff -U 8 -r mutt-1.5.21/curs_main.c mutt-1.5.21-with-x-label/curs_main.c
--- mutt-1.5.21/curs_main.c	2010-09-13 10:19:55.000000000 -0700
+++ mutt-1.5.21-with-x-label/curs_main.c	2011-12-12 15:53:47.000000000 -0800
@@ -1941,16 +1941,31 @@
         CHECK_VISIBLE;
 	CHECK_ATTACH;
 	if (option (OPTPGPAUTODEC) && (tag || !(CURHDR->security & PGP_TRADITIONAL_CHECKED)))
 	  mutt_check_traditional_pgp (tag ? NULL : CURHDR, &menu->redraw);
 	ci_send_message (SENDREPLY|SENDGROUPREPLY, NULL, NULL, Context, tag ? NULL : CURHDR);
 	menu->redraw = REDRAW_FULL;
 	break;
 
+      case OP_EDIT_LABEL:
+
+	CHECK_MSGCOUNT;
+	CHECK_READONLY;
+	rc = mutt_label_message(tag ? NULL : CURHDR);
+	if (rc > 0) {
+	  Context->changed = 1;
+	  menu->redraw = REDRAW_FULL;
+	  mutt_message ("%d label%s changed.", rc, rc == 1 ? "" : "s");
+	}
+	else {
+	  mutt_message _("No labels changed.");
+	}
+	break;
+
       case OP_LIST_REPLY:
 
 	CHECK_ATTACH;
 	CHECK_MSGCOUNT;
         CHECK_VISIBLE;
 	if (option (OPTPGPAUTODEC) && (tag || !(CURHDR->security & PGP_TRADITIONAL_CHECKED)))
 	  mutt_check_traditional_pgp (tag ? NULL : CURHDR, &menu->redraw);
 	ci_send_message (SENDREPLY|SENDLISTREPLY, NULL, NULL, Context, tag ? NULL : CURHDR);
diff -U 8 -r mutt-1.5.21/functions.h mutt-1.5.21-with-x-label/functions.h
--- mutt-1.5.21/functions.h	2010-08-24 09:34:21.000000000 -0700
+++ mutt-1.5.21-with-x-label/functions.h	2011-12-12 15:53:47.000000000 -0800
@@ -94,16 +94,17 @@
   { "copy-message",		OP_COPY_MESSAGE,		"C" },
   { "decode-copy",		OP_DECODE_COPY,			"\033C" },
   { "decode-save",		OP_DECODE_SAVE,			"\033s" },
   { "delete-message",		OP_DELETE,			"d" },
   { "delete-pattern",		OP_MAIN_DELETE_PATTERN,		"D" },
   { "delete-thread",		OP_DELETE_THREAD,		"\004" },
   { "delete-subthread",		OP_DELETE_SUBTHREAD,		"\033d" },
   { "edit",			OP_EDIT_MESSAGE,		"e" },
+  { "edit-label",      OP_EDIT_LABEL,       "y" },
   { "edit-type",		OP_EDIT_TYPE,			"\005" },
   { "forward-message",		OP_FORWARD_MESSAGE,		"f" },
   { "flag-message",		OP_FLAG_MESSAGE,		"F" },
   { "group-reply",		OP_GROUP_REPLY,			"g" },
 #ifdef USE_POP
   { "fetch-mail",		OP_MAIN_FETCH_MAIL,		"G" },
 #endif
 #ifdef USE_IMAP
@@ -182,16 +183,17 @@
   { "copy-message",	OP_COPY_MESSAGE,		"C" },
   { "decode-copy",	OP_DECODE_COPY,			"\033C" },
   { "delete-message",	OP_DELETE,			"d" },
   { "delete-thread",	OP_DELETE_THREAD,		"\004" },
   { "delete-subthread",	OP_DELETE_SUBTHREAD,		"\033d" },
   { "set-flag",  	OP_MAIN_SET_FLAG,		"w" },
   { "clear-flag",       OP_MAIN_CLEAR_FLAG,		"W" },
   { "edit",		OP_EDIT_MESSAGE,		"e" },
+  { "edit-label", OP_EDIT_LABEL,       "y" },
   { "edit-type",	OP_EDIT_TYPE,			"\005" },
   { "forward-message",	OP_FORWARD_MESSAGE,		"f" },
   { "flag-message",	OP_FLAG_MESSAGE,		"F" },
   { "group-reply",	OP_GROUP_REPLY,			"g" },
 #ifdef USE_IMAP
   { "imap-fetch-mail",  OP_MAIN_IMAP_FETCH,		NULL },
   { "imap-logout-all",  OP_MAIN_IMAP_LOGOUT_ALL,	NULL },
 #endif
diff -U 8 -r mutt-1.5.21/headers.c mutt-1.5.21-with-x-label/headers.c
--- mutt-1.5.21/headers.c	2009-08-25 12:08:52.000000000 -0700
+++ mutt-1.5.21-with-x-label/headers.c	2011-12-12 15:53:47.000000000 -0800
@@ -210,8 +210,64 @@
       tmp       = cur;
       *last     = cur->next;
       cur       = cur->next;
       tmp->next = NULL;
       mutt_free_list (&tmp);
     }
   }
 }
+
+/*
+ * dgc: Add an X-Label: field.
+ */
+static int label_message(HEADER *hdr, char *new)
+{
+	if (hdr == NULL)
+		return 0;
+	if (hdr->env->x_label == NULL && new == NULL)
+		return 0;
+	if (hdr->env->x_label != NULL && new != NULL &&
+			strcmp(hdr->env->x_label, new) == 0)
+		return 0;
+	if (hdr->env->x_label != NULL)
+		FREE(&hdr->env->x_label);
+	if (new == NULL)
+		hdr->env->x_label = NULL;
+	else
+		hdr->env->x_label = safe_strdup(new);
+	return hdr->changed = hdr->xlabel_changed = 1;
+}
+
+int mutt_label_message(HEADER *hdr)
+{
+	char buf[LONG_STRING], *new;
+	int i;
+	int changed;
+
+	*buf = '\0';
+	if (hdr != NULL && hdr->env->x_label != NULL) {
+		strncpy(buf, hdr->env->x_label, LONG_STRING);
+	}
+
+	mutt_get_field("Label: ", buf, sizeof(buf), M_CLEAR);
+	new = buf;
+	SKIPWS(new);
+	if (*new == '\0')
+		new = NULL;
+
+	changed = 0;
+	if (hdr != NULL) {
+		changed += label_message(hdr, new);
+	} else {
+#define HDR_OF(index)	Context->hdrs[Context->v2r[(index)]]
+		for (i = 0; i < Context->vcount; ++i) {
+			if (HDR_OF(i)->tagged)
+				if (label_message(HDR_OF(i), new)) {
+					++changed;
+					mutt_set_flag(Context, HDR_OF(i),
+						M_TAG, 0);
+				}
+		}
+	}
+
+	return changed;
+}
diff -U 8 -r mutt-1.5.21/mutt.h mutt-1.5.21-with-x-label/mutt.h
--- mutt-1.5.21/mutt.h	2010-09-13 10:19:55.000000000 -0700
+++ mutt-1.5.21-with-x-label/mutt.h	2011-12-12 15:53:47.000000000 -0800
@@ -719,16 +719,18 @@
   unsigned int display_subject : 1; 	/* used for threading */
   unsigned int recip_valid : 1;  	/* is_recipient is valid */
   unsigned int active : 1;	    	/* message is not to be removed */
   unsigned int trash : 1;		/* message is marked as trashed on disk.
 					 * This flag is used by the maildir_trash
 					 * option.
 					 */
   
+  unsigned int xlabel_changed : 1;	/* editable - used for syncing */
+
   /* timezone of the sender of this message */
   unsigned int zhours : 5;
   unsigned int zminutes : 6;
   unsigned int zoccident : 1;
 
   /* bits used for caching when searching */
   unsigned int searched : 1;
   unsigned int matched : 1;
diff -U 8 -r mutt-1.5.21/protos.h mutt-1.5.21-with-x-label/protos.h
--- mutt-1.5.21/protos.h	2010-08-24 09:34:21.000000000 -0700
+++ mutt-1.5.21-with-x-label/protos.h	2011-12-12 15:55:09.000000000 -0800
@@ -177,16 +177,17 @@
 void mutt_decode_attachment (BODY *, STATE *);
 void mutt_decode_base64 (STATE *s, long len, int istext, iconv_t cd);
 void mutt_default_save (char *, size_t, HEADER *);
 void mutt_display_address (ENVELOPE *);
 void mutt_display_sanitize (char *);
 void mutt_edit_content_type (HEADER *, BODY *, FILE *);
 void mutt_edit_file (const char *, const char *);
 void mutt_edit_headers (const char *, const char *, HEADER *, char *, size_t);
+int mutt_label_message (HEADER *);
 int mutt_filter_unprintable (char **);
 void mutt_curses_error (const char *, ...);
 void mutt_curses_message (const char *, ...);
 void mutt_encode_path (char *, size_t, const char *);
 void mutt_enter_command (void);
 void mutt_expand_aliases_env (ENVELOPE *);
 void mutt_expand_file_fmt (char *, size_t, const char *, const char *);
 void mutt_expand_fmt (char *, size_t, const char *, const char *);