diff --git a/TODO.md b/TODO.md
index 748585c..2e786aa 100644
--- a/TODO.md
+++ b/TODO.md
@@ -4,8 +4,6 @@
 
 ## Current work
 
-* `eb_add_property()` should duplicate and free string argument
-* add `cp_add_tag(cp, offset, kbuf)`?
 * `S-TAB` -> untabify
 * `TAB` and `S-TAB` with selected block -> indent, unindent block
 * `C-x (` should restart macro learning mode
diff --git a/buffer.c b/buffer.c
index 4ff0ef1..f4f208b 100644
--- a/buffer.c
+++ b/buffer.c
@@ -2,7 +2,7 @@
  * Buffer handling for QEmacs
  *
  * Copyright (c) 2000-2002 Fabrice Bellard.
- * Copyright (c) 2002-2023 Charlie Gordon.
+ * Copyright (c) 2002-2024 Charlie Gordon.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -2678,21 +2678,10 @@ void eb_add_property(EditBuffer *b, int offset, int type, void *data) {
         eb_add_callback(b, eb_plist_callback, NULL, 0);
     }
 
+    /* insert property in ascending order of offset */
     for (pp = &b->property_list; (p = *pp) != NULL; pp = &(*pp)->next) {
-        if (p->offset >= offset) {
-            if (p->offset == offset) {
-                if (p->type == type && type == QE_PROP_TAG) {
-                    /* prevent tag duplicates */
-                    if (strequal(p->data, data)) {
-                        if (type & QE_PROP_FREE)
-                            qe_free(&data);
-                        return;
-                    }
-                }
-                continue;
-            }
+        if (p->offset > offset)
             break;
-        }
     }
 
     p = qe_mallocz(QEProperty);
@@ -2703,6 +2692,17 @@ void eb_add_property(EditBuffer *b, int offset, int type, void *data) {
     *pp = p;
 }
 
+void eb_add_tag(EditBuffer *b, int offset, const char *s) {
+    QEProperty *p;
+
+    /* prevent tag duplicates */
+    for (p = b->property_list; p != NULL; p = p->next) {
+        if (p->offset == offset && p->type == QE_PROP_TAG && strequal(p->data, s))
+            return;
+    }
+    eb_add_property(b, offset, QE_PROP_TAG, qe_strdup(s));
+}
+
 QEProperty *eb_find_property(EditBuffer *b, int offset, int offset2, int type) {
     QEProperty *found = NULL;
     QEProperty *p;
diff --git a/lang/clang.c b/lang/clang.c
index 9f7b428..ab8b09d 100644
--- a/lang/clang.c
+++ b/lang/clang.c
@@ -598,8 +598,7 @@ static void c_colorize_line(QEColorizeContext *cp,
                     i2++;
 
                 if (tag && qe_findchar("({[,;=", str[i1])) {
-                    eb_add_property(cp->b, cp->offset + start,
-                                    QE_PROP_TAG, qe_strdup(kbuf));
+                    eb_add_tag(cp->b, cp->offset + start, kbuf);
                 }
 
                 if ((start == 0 || str[start - 1] != '.')
@@ -1694,7 +1693,7 @@ static int get_js_identifier(char *dest, int size, char32_t c,
     int pos = 0, j = i;
 
     if (c == 0) {
-        if (!(i < n && is_js_identifier_start(c = str[i++]))) {
+        if (!(j < n && is_js_identifier_start(c = str[j++]))) {
             if (size > 0)
                 *dest = '\0';
             return 0;
@@ -1996,16 +1995,14 @@ static void js_colorize_line(QEColorizeContext *cp,
                     style = C_STYLE_FUNCTION;
                     if (tag) {
                         /* tag function definition */
-                        eb_add_property(cp->b, cp->offset + start,
-                                        QE_PROP_TAG, qe_strdup(kbuf));
+                        eb_add_tag(cp->b, cp->offset + start, kbuf);
                         tag = 0;
                     }
                     break;
                 } else
                 if (tag && qe_findchar("(,;=", str[i1])) {
                     /* tag variable definition */
-                    eb_add_property(cp->b, cp->offset + start,
-                                    QE_PROP_TAG, qe_strdup(kbuf));
+                    eb_add_tag(cp->b, cp->offset + start, kbuf);
                 }
 
                 if ((start == 0 || str[start - 1] != '.')
@@ -3813,16 +3810,14 @@ static void salmon_colorize_line(QEColorizeContext *cp,
                     style = C_STYLE_FUNCTION;
                     if (tag) {
                         /* tag function definition */
-                        eb_add_property(cp->b, cp->offset + start,
-                                        QE_PROP_TAG, qe_strdup(kbuf));
+                        eb_add_tag(cp->b, cp->offset + start, kbuf);
                         tag = 0;
                     }
                     break;
                 } else
                 if (tag && qe_findchar("(,;=", str[i1])) {
                     /* tag variable definition */
-                    eb_add_property(cp->b, cp->offset + start,
-                                    QE_PROP_TAG, qe_strdup(kbuf));
+                    eb_add_tag(cp->b, cp->offset + start, kbuf);
                 }
 
                 if ((start == 0 || str[start - 1] != '.')
@@ -4202,9 +4197,8 @@ static void ppl_colorize_line(QEColorizeContext *cp,
                         &&  strfind("function|creator|command|template|service|factory|type", kbuf))
                         {
                             int fstart = cp_skip_blanks(str, i, n);
-                            if (get_js_identifier(kbuf, countof(kbuf), 0, str, fstart, n)) {
-                                eb_add_property(cp->b, cp->offset + fstart, QE_PROP_TAG, qe_strdup(kbuf));
-                            }
+                            if (get_js_identifier(kbuf, countof(kbuf), 0, str, fstart, n))
+                                eb_add_tag(cp->b, cp->offset + start, kbuf);
                         } else
                         if (start == indent && strfind("java|java_header", kbuf)) {
                             state |= IN_PPL_JAVA;
diff --git a/lang/python.c b/lang/python.c
index 4ab469b..732b85c 100644
--- a/lang/python.c
+++ b/lang/python.c
@@ -282,8 +282,7 @@ static void python_colorize_line(QEColorizeContext *cp,
                     style = PYTHON_STYLE_FUNCTION;
                     if (tag) {
                         /* tag function definition */
-                        eb_add_property(cp->b, cp->offset + start,
-                                        QE_PROP_TAG, qe_strdup(kbuf));
+                        eb_add_tag(cp->b, cp->offset + start, kbuf);
                         tag = 0;
                     }
                     break;
@@ -293,8 +292,7 @@ static void python_colorize_line(QEColorizeContext *cp,
                         continue;
                     if (qe_findchar(",=", str[i1])) {
                         /* tag variable definition */
-                        eb_add_property(cp->b, cp->offset + start,
-                                        QE_PROP_TAG, qe_strdup(kbuf));
+                        eb_add_tag(cp->b, cp->offset + start, kbuf);
                         /* XXX: should colorize variable definition */
                     }
                 }
diff --git a/modes/fractal.c b/modes/fractal.c
index 053ad9a..a3bad39 100644
--- a/modes/fractal.c
+++ b/modes/fractal.c
@@ -181,8 +181,7 @@ static void fractint_colorize_line(QEColorizeContext *cp,
                     }
                     style = FRACTINT_STYLE_COMMENT;
                 } else {
-                    eb_add_property(cp->b, cp->offset + start,
-                                    QE_PROP_TAG, qe_strdup(kbuf));
+                    eb_add_tag(cp->b, cp->offset + start, kbuf);
                     style = FRACTINT_STYLE_DEFINITION;
                 }
                 break;
diff --git a/qe.h b/qe.h
index 11a86ca..a1e7b0f 100644
--- a/qe.h
+++ b/qe.h
@@ -595,6 +595,7 @@ struct QEProperty {
 
 void eb_add_property(EditBuffer *b, int offset, int type, void *data);
 QEProperty *eb_find_property(EditBuffer *b, int offset, int offset2, int type);
+void eb_add_tag(EditBuffer *b, int offset, const char *s);
 void eb_delete_properties(EditBuffer *b, int offset, int offset2);
 
 /* qe module handling */