diff --git a/epan/dissectors/packet-afp.c b/epan/dissectors/packet-afp.c
index bfafc15c81..2344de22da 100644
--- a/epan/dissectors/packet-afp.c
+++ b/epan/dissectors/packet-afp.c
@@ -1723,7 +1723,7 @@ get_name(tvbuff_t *tvb, int offset, int type)
 		string = tvb_format_text(tvb,offset, len);
     		break;
 	default:
-		string = "unknow type";
+		string = "Unknown type";
 		break;
     	}
 	return string;
@@ -1902,7 +1902,7 @@ dissect_reply_afp_get_server_param(tvbuff_t *tvb, packet_info *pinfo _U_, proto_
 
 		len  = tvb_get_guint8(tvb, offset) +1;
 		rep = get_name(tvb, offset, 2);
-		proto_item_set_text(item, rep);
+		proto_item_set_text(item, "%s", rep);
 		proto_item_set_len(item, len +1);
 
 		proto_tree_add_item(tree, hf_afp_vol_name, tvb, offset, 1,FALSE);
diff --git a/epan/dissectors/packet-ansi_637.c b/epan/dissectors/packet-ansi_637.c
index 8285ed698f..f741e63e74 100644
--- a/epan/dissectors/packet-ansi_637.c
+++ b/epan/dissectors/packet-ansi_637.c
@@ -1716,7 +1716,7 @@ dissect_ansi_637_trans_param(tvbuff_t *tvb, proto_tree *tree, guint32 *offset)
 
 	    if (ansi_637_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, ansi_637_add_string);
+		proto_item_append_text(item, "%s", ansi_637_add_string);
 	    }
 	}
 
diff --git a/epan/dissectors/packet-ansi_a.c b/epan/dissectors/packet-ansi_a.c
index 9e7c365bb3..f66613a814 100644
--- a/epan/dissectors/packet-ansi_a.c
+++ b/epan/dissectors/packet-ansi_a.c
@@ -1992,7 +1992,7 @@ elem_cell_id_list(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gc
 
 	if (add_string[0] != '\0')
 	{
-	    proto_item_append_text(item, add_string);
+	    proto_item_append_text(item, "%s", add_string);
 	}
 
 	proto_item_set_len(item, consumed);
@@ -2189,7 +2189,7 @@ elem_downlink_re(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gch
 
 	if (add_string[0] != '\0')
 	{
-	    proto_item_append_text(item, add_string);
+	    proto_item_append_text(item, "%s", add_string);
 	}
 
 	proto_item_set_len(item, consumed);
@@ -2337,7 +2337,7 @@ elem_ho_pow_lev(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
 
     if (add_string[0] != '\0')
     {
-	proto_item_append_text(item, add_string);
+	proto_item_append_text(item, "%s", add_string);
     }
 
     proto_item_set_len(item, consumed);
@@ -2380,7 +2380,7 @@ elem_ho_pow_lev(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
 
 	if (add_string[0] != '\0')
 	{
-	    proto_item_append_text(item, add_string);
+	    proto_item_append_text(item, "%s", add_string);
 	}
 
 	proto_item_set_len(item, consumed);
@@ -6055,7 +6055,7 @@ elem_tlv(tvbuff_t *tvb, proto_tree *tree, elem_idx_t idx, guint32 offset, guint
 
 		if (a_add_string[0] != '\0')
 		{
-		    proto_item_append_text(item, a_add_string);
+		    proto_item_append_text(item, "%s", a_add_string);
 		    a_add_string[0] = '\0';
 		}
 	    }
@@ -6117,7 +6117,7 @@ elem_tv(tvbuff_t *tvb, proto_tree *tree, elem_idx_t idx, guint32 offset, gchar *
 
 	    if (a_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, a_add_string);
+		proto_item_append_text(item, "%s", a_add_string);
 		a_add_string[0] = '\0';
 	    }
 	}
@@ -6210,7 +6210,7 @@ elem_lv(tvbuff_t *tvb, proto_tree *tree, elem_idx_t idx, guint32 offset, guint l
 
 	    if (a_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, a_add_string);
+		proto_item_append_text(item, "%s", a_add_string);
 		a_add_string[0] = '\0';
 	    }
 	}
diff --git a/epan/dissectors/packet-ansi_map.c b/epan/dissectors/packet-ansi_map.c
index 13e14f431e..bf4710db16 100644
--- a/epan/dissectors/packet-ansi_map.c
+++ b/epan/dissectors/packet-ansi_map.c
@@ -12811,7 +12811,7 @@ dissect_ansi_param(ASN1_SCK *asn1, proto_tree *tree)
 
 	    if (ansi_map_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, ansi_map_add_string);
+		proto_item_append_text(item, "%s", ansi_map_add_string);
 		ansi_map_add_string[0] = '\0';
 	    }
 	}
@@ -12869,7 +12869,7 @@ dissect_ansi_params(ASN1_SCK *asn1, proto_tree *tree)
 
     if (ansi_map_add_string[0] != '\0')
     {
-	proto_item_append_text(item, ansi_map_add_string);
+	proto_item_append_text(item, "%s", ansi_map_add_string);
 	ansi_map_add_string[0] = '\0';
     }
 }
diff --git a/epan/dissectors/packet-dcerpc-spoolss.c b/epan/dissectors/packet-dcerpc-spoolss.c
index a50ded5bb6..764de68e2a 100644
--- a/epan/dissectors/packet-dcerpc-spoolss.c
+++ b/epan/dissectors/packet-dcerpc-spoolss.c
@@ -1704,7 +1704,7 @@ dissect_spoolss_relstrarray(tvbuff_t *tvb, int offset, packet_info *pinfo,
 
 	relstr_len = relstr_end - relstr_start;
 
-	proto_item_append_text(item, text);
+	proto_item_append_text(item, "%s", text);
 
 	if (data)
 		*data = text;
@@ -6325,7 +6325,7 @@ dissect_spoolss_printer_enum_values(tvbuff_t *tvb, int offset,
 
 	subtree = proto_item_add_subtree(item, ett_printer_enumdataex_value);
 
-	proto_item_append_text(item, name);
+	proto_item_append_text(item, "%s", name);
 			       
 	proto_tree_add_text(
 		subtree, tvb, offset - 8, 4, "Name offset: %d", name_offset);
diff --git a/epan/dissectors/packet-gsm_a.c b/epan/dissectors/packet-gsm_a.c
index 8a28eb37e4..f98e9240fb 100644
--- a/epan/dissectors/packet-gsm_a.c
+++ b/epan/dissectors/packet-gsm_a.c
@@ -2208,7 +2208,7 @@ be_cell_id_list(tvbuff_t *tvb, proto_tree *tree, guint32 offset, guint len, gcha
 
 	if (add_string[0] != '\0')
 	{
-	    proto_item_append_text(item, add_string);
+	    proto_item_append_text(item, "%s", add_string);
 	}
 
 	proto_item_set_len(item, consumed);
@@ -11356,7 +11356,7 @@ elem_tlv(tvbuff_t *tvb, proto_tree *tree, guint8 iei, gint pdu_type, int idx, gu
 
 		if (a_add_string[0] != '\0')
 		{
-		    proto_item_append_text(item, a_add_string);
+		    proto_item_append_text(item, "%s", a_add_string);
 		    a_add_string[0] = '\0';
 		}
 	    }
@@ -11425,7 +11425,7 @@ elem_tv(tvbuff_t *tvb, proto_tree *tree, guint8 iei, gint pdu_type, int idx, gui
 
 	    if (a_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, a_add_string);
+		proto_item_append_text(item, "%s", a_add_string);
 		a_add_string[0] = '\0';
 	    }
 	}
@@ -11498,7 +11498,7 @@ elem_tv_short(tvbuff_t *tvb, proto_tree *tree, guint8 iei, gint pdu_type, int id
 
 	    if (a_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, a_add_string);
+		proto_item_append_text(item, "%s", a_add_string);
 		a_add_string[0] = '\0';
 	    }
 	}
@@ -11598,7 +11598,7 @@ elem_lv(tvbuff_t *tvb, proto_tree *tree, gint pdu_type, int idx, guint32 offset,
 
 	    if (a_add_string[0] != '\0')
 	    {
-		proto_item_append_text(item, a_add_string);
+		proto_item_append_text(item, "%s", a_add_string);
 		a_add_string[0] = '\0';
 	    }
 	}
diff --git a/epan/dissectors/packet-iapp.c b/epan/dissectors/packet-iapp.c
index 97325c885b..dcf03d9333 100644
--- a/epan/dissectors/packet-iapp.c
+++ b/epan/dissectors/packet-iapp.c
@@ -320,7 +320,7 @@ append_pduval_str(proto_item *ti, int type, int len, tvbuff_t *tvb, int offset,
 					{
 						if (!first)
 							proto_item_append_text(ti, " ");
-						proto_item_append_text(ti, strval);
+						proto_item_append_text(ti, "%s", strval);
 					}
 				}
 			proto_item_append_text(ti, ")");
diff --git a/epan/dissectors/packet-ncp2222.inc b/epan/dissectors/packet-ncp2222.inc
index 5bf24b2b4d..9f462241c9 100644
--- a/epan/dissectors/packet-ncp2222.inc
+++ b/epan/dissectors/packet-ncp2222.inc
@@ -1142,7 +1142,7 @@ padd_date(ptvcursor_t *ptvc, const ptvc_record *rec)
 
 	uint_to_nwdate(get_item_value(item), &nw_date);
 	
-	proto_item_set_text(item, get_item_name(item)); 
+	proto_item_set_text(item, "%s", get_item_name(item)); 
 	proto_item_append_text(item, ": %04u/%02u/%02u",
 			nw_date.year, nw_date.month, nw_date.day);
 	return item;
@@ -1162,7 +1162,7 @@ padd_time(ptvcursor_t *ptvc, const ptvc_record *rec)
 
 	uint_to_nwtime(get_item_value(item), &nw_time);
 	
-	proto_item_set_text(item, get_item_name(item)); 
+	proto_item_set_text(item, "%s", get_item_name(item)); 
 	proto_item_append_text(item, ": %02u:%02u:%02u",
 			nw_time.hour, nw_time.minute, nw_time.second);
 	return item;
@@ -1185,7 +1185,7 @@ padd_uni(ptvcursor_t *ptvc, const ptvc_record *rec)
 	item = ptvcursor_add(ptvc, *rec->hf_ptr,
 		rec->length, rec->endianness);
 
-        proto_item_set_text(item, get_item_name(item)); 
+        proto_item_set_text(item, "%s", get_item_name(item)); 
 	proto_item_append_text(item, " %s",
 			nw_uni.buffer);
                                 
diff --git a/epan/dissectors/packet-per.c b/epan/dissectors/packet-per.c
index 5adaff5d6d..c5ce0c34e9 100644
--- a/epan/dissectors/packet-per.c
+++ b/epan/dissectors/packet-per.c
@@ -1036,7 +1036,7 @@ DEBUG_ENTRY("dissect_per_choice");
 		} else {
 			guint32 new_offset;
 
-			proto_item_set_text(choiceitem, choice[index].name);
+			proto_item_set_text(choiceitem, "%s", choice[index].name);
 			new_offset=choice[index].func(tvb, offset, pinfo, choicetree);
 
 			if((new_offset>(offset+(length*8)))||((new_offset+8)<(offset+length*8))){
diff --git a/epan/dissectors/packet-rsvp.c b/epan/dissectors/packet-rsvp.c
index 1553215e9c..9b45366104 100644
--- a/epan/dissectors/packet-rsvp.c
+++ b/epan/dissectors/packet-rsvp.c
@@ -1237,7 +1237,7 @@ dissect_rsvp_session (proto_tree *ti, tvbuff_t *tvb,
     proto_tree_add_text(rsvp_object_tree, tvb, offset+2, 1,
 			"Class number: %u - %s",
 			class, type_str);
-    proto_item_set_text(ti, summary_session(tvb, offset));
+    proto_item_set_text(ti, "%s", summary_session(tvb, offset));
 
     switch(type) {
     case RSVP_SESSION_TYPE_IPV4:
@@ -1866,7 +1866,7 @@ dissect_rsvp_template_filter (proto_tree *ti, tvbuff_t *tvb,
 	break;
     }
 
-     proto_item_set_text(ti, summary_template(tvb, offset));
+     proto_item_set_text(ti, "%s", summary_template(tvb, offset));
      switch(type) {
      case 1:
 	 proto_tree_add_text(rsvp_object_tree, tvb, offset+3, 1,
diff --git a/epan/dissectors/packet-slowprotocols.c b/epan/dissectors/packet-slowprotocols.c
index ba3ca3f131..f81b1da499 100644
--- a/epan/dissectors/packet-slowprotocols.c
+++ b/epan/dissectors/packet-slowprotocols.c
@@ -841,7 +841,7 @@ static const char cont_sep[] = ", ";
         if(item){                        \
             string = get_manuf_name(mac); \
             proto_item_append_text(item, " (");    \
-            proto_item_append_text(item, string);    \
+            proto_item_append_text(item, "%s", string);    \
             proto_item_append_text(item, ")");    \
         }
 
diff --git a/epan/proto.h b/epan/proto.h
index 0744be19f9..32761ea20a 100644
--- a/epan/proto.h
+++ b/epan/proto.h
@@ -907,7 +907,19 @@ proto_tree_add_debug_text(proto_tree *tree, const char *format,
 
 
 
-/** Append a string to a protocol item.
+/** Append a string to a protocol item.<br>
+    NOTE: this function will break with the TRY_TO_FAKE_THIS_ITEM()
+    speed optimization.
+    Currently only WSP use this function so it is not that bad but try to
+    avoid using this one if possible.
+    IF you must use this function you MUST also disable the
+    TRY_TO_FAKE_THIS_ITEM() optimization for your dissector/function
+    using proto_item_append_string().
+    Do that by faking that the tree is visible by setting :
+    PTREE_DATA(tree)->visible=1;  (see packet-wsp.c)
+    BEFORE you create the item you are later going to use
+    proto_item_append_string() on.
+
  @param pi the item to append the string to
  @param str the string to append */
 extern void
diff --git a/plugins/irda/packet-irda.c b/plugins/irda/packet-irda.c
index f8332b122f..53e50258d6 100644
--- a/plugins/irda/packet-irda.c
+++ b/plugins/irda/packet-irda.c
@@ -949,7 +949,7 @@ gboolean check_iap_octet_result(tvbuff_t* tvb, proto_tree* tree, unsigned offset
         if (tree)
         {
             proto_item* ti = proto_tree_add_item(tree, hf_iap_invaloctet, tvb, offset, 0, FALSE);
-            proto_item_append_text(ti, attr_name);
+            proto_item_append_text(ti, "%s", attr_name);
             proto_item_append_text(ti, "\" attribute must be octet sequence!");
         }
 
@@ -975,7 +975,7 @@ guint8 check_iap_lsap_result(tvbuff_t* tvb, proto_tree* tree, unsigned offset,
         if (tree)
         {
             proto_item* ti = proto_tree_add_item(tree, hf_iap_invallsap, tvb, offset, 0, FALSE);
-            proto_item_append_text(ti, attr_name);
+            proto_item_append_text(ti, "%s", attr_name);
             proto_item_append_text(ti, "\" attribute must be integer value between 0x01 and 0x6F!");
         }
 
diff --git a/plugins/profinet/packet-pn-dcp.c b/plugins/profinet/packet-pn-dcp.c
index f3c75da900..4dcdafd797 100644
--- a/plugins/profinet/packet-pn-dcp.c
+++ b/plugins/profinet/packet-pn-dcp.c
@@ -334,7 +334,7 @@ pn_append_info(packet_info *pinfo, proto_item *dcp_item, char *text)
     if (check_col(pinfo->cinfo, COL_INFO))
         col_append_fstr(pinfo->cinfo, COL_INFO, text);
 
-    proto_item_append_text(dcp_item, text);
+    proto_item_append_text(dcp_item, "%s", text);
 }