Index: core/abc2svg.js
==================================================================
--- core/abc2svg.js
+++ core/abc2svg.js
@@ -1,8 +1,8 @@
 // abc2svg - abc2svg.js
 //
-// Copyright (C) 2014-2021 Jean-Francois Moine
+// Copyright (C) 2014-2022 Jean-Francois Moine
 //
 // This file is part of abc2svg-core.
 //
 // abc2svg-core is free software: you can redistribute it and/or modify
 // it under the terms of the GNU Lesser General Public License as published by
@@ -27,10 +27,11 @@
 
 	// symbol types
 	BAR: 0,
 	CLEF: 1,
 	CUSTOS: 2,
+	SM: 3,		// sequence marker (transient)
 	GRACE: 4,
 	KEY: 5,
 	METER: 6,
 	MREST: 7,
 	NOTE: 8,
@@ -61,11 +62,11 @@
 		SL_CENTER: 0x20,
 		SL_CLOSE: 0x40
     };
 
 // !! tied to the symbol types in abc2svg.js !!
-abc2svg.sym_name = ['bar', 'clef', 'custos', '', 'grace',
+abc2svg.sym_name = ['bar', 'clef', 'custos', 'smark', 'grace',
 		'key', 'meter', 'Zrest', 'note', 'part',
 		'rest', 'yspace', 'staves', 'Break', 'tempo',
 		'', 'block', 'remark']
 
 	// key table - index = number of accidentals + 7

Index: core/parse.js
==================================================================
--- core/parse.js
+++ core/parse.js
@@ -1437,10 +1437,14 @@
 		curvoice.sym_restart = s
 
 	sym_link(s);
 
 	s.st = curvoice.st			/* original staff */
+
+	// if space before the bar, update its time (see w_tb[])
+	if (s.prev && s.prev.type == C.SPACE)
+		s.prev.time--
 
 	/* if repeat bar and shift, add a repeat bar */
 	if (s.rbstart
 	 && bar_type != "["
 	 && !curvoice.norepbra

Index: core/tune.js
==================================================================
--- core/tune.js
+++ core/tune.js
@@ -117,22 +117,22 @@
 }
 
 /* -- sort all symbols by time and vertical sequence -- */
 // weight of the symbols !! depends on the symbol type !!
 var w_tb = new Uint8Array([
-	5,	// bar
+	4,	// bar
 	1,	// clef
 	8,	// custos
-	0,	// (free)
+	5,	// sm (sequence marker)
 	0,	// grace
 	2,	// key
 	3,	// meter
 	9,	// mrest
 	9,	// note
 	0,	// part
 	9,	// rest
-	4,	// space
+	6,	// space (after bar)
 	0,	// staves
 	7,	// stbrk
 	0,	// tempo
 	0,	// (free)
 	0,	// block
@@ -243,12 +243,21 @@
 				break
 			s = vtb[v]
 			if (!s || s.time != time
 			 || w_tb[s.type] != wmin)
 				continue
-			if (s.type == C.STAVES)
+			if (s.type == C.STAVES) {
 				new_sy = s.sy
+			} else if (s.type == C.SM) {	// if a sequence marker
+				s.next.prev = s.prev	// remove it
+				if (s.prev)
+					s.prev.next = s.next
+				else
+					s.p_v.sym = s.next
+				vtb[v] = s.next
+				continue
+			}
 			if (fl) {
 				fl = 0;
 				s.seqst = true
 			}
 			s.ts_prev = prev
@@ -349,10 +358,32 @@
 		for (s = p_voice.sym; s; s = s.next) {
 			if (s.time >= staves_found)
 				break
 		}
 		for ( ; s; s = s.next) {
+
+			// if the symbol has no sequence weight
+			// and if there a time skip,
+			// add a sequence marker before it
+			if (!w_tb[s.type]
+			 && (!s.prev || s.time > s.prev.time + s.prev.dur)) {
+				s2 = {
+					type: C.SM,
+					v: s.v,
+					p_v: s.p_v,
+					time: s.time,
+					dur:0,
+					next: s,
+					prev: s.prev
+				}
+				if (s.prev)
+					s.prev.next = s2
+				else
+					voice_tb[s.v].sym = s2
+				s.prev = s2
+			}
+
 			switch (s.type) {
 			case C.GRACE:
 				if (!cfmt.graceword)
 					continue
 				for (s2 = s.next; s2; s2 = s2.next) {
@@ -1806,22 +1837,10 @@
 				vover.p_voice.time = curvoice.time
 		}
 	}
 	p_voice2.time = vover.time;
 	curvoice = p_voice2
-
-	// add a bar at start of the measure overlay
-	// (needed for sort_all() in case of spaces - 'y')
-	if (vover.bar && vover.time) {
-		sym_link({
-			type: C.BAR,
-			bar_type: vover.bar,
-			invis: 1,
-			dur: 0,
-			multi: 0
-		})
-	}
 }
 
 // check if a clef, key or time signature may go at start of the current voice
 function is_voice_sig() {
 	var s