diff --git a/crates/ui-egui/src/chrome/control_bar.rs b/crates/ui-egui/src/chrome/control_bar.rs
index 2f4f8c7b9..f2c41b4df 100644
--- a/crates/ui-egui/src/chrome/control_bar.rs
+++ b/crates/ui-egui/src/chrome/control_bar.rs
@@ -190,6 +190,7 @@ pub fn control_bar(app: &mut VectorcraftApp, ui: &mut Ui) {
                 let image = crate::place::control_bar_details(app, ui) || crate::panels::image_trace::control_bar(app, ui);
                 crate::toolbar::control_bar_options(app, ui);
                 crate::dialogs::envelope::control_bar(app, ui);
+                crate::panels::symbols::control_bar(app, ui);
                 let opacity = if first.is_some() { crate::panels::current_transparency(app).map_or(1.0, |t| t.0) } else { 1.0 };
                 if !image {
                     let shown_stroke = crate::panels::current_stroke(app);
diff --git a/crates/ui-egui/src/i18n/bg.tsv b/crates/ui-egui/src/i18n/bg.tsv
index acb56f53e..60522f664 100644
--- a/crates/ui-egui/src/i18n/bg.tsv
+++ b/crates/ui-egui/src/i18n/bg.tsv
@@ -2583,6 +2583,7 @@ font-technology	Variable	Променливи
 	Repeat Tab	Повтаряне на табулатора
 	Repeat {name}	Повтаряне на {name}
 	Replace	Замяна
+	Replace:	Замяна:
 	Replace Font	Замяна на шрифт
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Заменете го с друг файл или го игнорирайте: неговите изображения ще продължат да показват записания с документа преглед.
 	Replace Spine	Замяна на оста
diff --git a/crates/ui-egui/src/i18n/ca.tsv b/crates/ui-egui/src/i18n/ca.tsv
index 08b907471..2148f134e 100644
--- a/crates/ui-egui/src/i18n/ca.tsv
+++ b/crates/ui-egui/src/i18n/ca.tsv
@@ -3285,6 +3285,7 @@
 	Repeat {name}	Repeteix {name}
 	Repeating	Repetició
 	Replace	Reemplaça
+	Replace:	Reemplaça:
 	Replace Font	Reemplaça el tipus de lletra
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Reemplaça’l per un altre fitxer o ignora’l: les seves imatges continuaran mostrant la previsualització desada amb el document.
 	Replace Spine	Reemplaça l’espina
diff --git a/crates/ui-egui/src/i18n/cs.tsv b/crates/ui-egui/src/i18n/cs.tsv
index 91bdee122..97082fd79 100644
--- a/crates/ui-egui/src/i18n/cs.tsv
+++ b/crates/ui-egui/src/i18n/cs.tsv
@@ -3800,6 +3800,7 @@ axis	Both	Obě
 	Set Text	Nastavit text
 	Insert Character	Vložit znak
 	Replace	Nahradit
+	Replace:	Nahradit:
 	Type on a Path Options	Možnosti textu na cestě
 	Highlight Variable	Zvýraznit proměnnou
 	New Variable	Nová proměnná
diff --git a/crates/ui-egui/src/i18n/da.tsv b/crates/ui-egui/src/i18n/da.tsv
index 5c01df3c6..3ab958c4b 100644
--- a/crates/ui-egui/src/i18n/da.tsv
+++ b/crates/ui-egui/src/i18n/da.tsv
@@ -3537,6 +3537,7 @@ axis	Both	Begge
 	Set Text	Angiv tekst
 	Insert Character	Indsæt tegn
 	Replace	Erstat
+	Replace:	Erstat:
 	Type on a Path Options	Indstillinger for tekst på kurve
 	Highlight Variable	Fremhæv variabel
 	New Variable	Ny variabel
diff --git a/crates/ui-egui/src/i18n/de.tsv b/crates/ui-egui/src/i18n/de.tsv
index b58127892..c3cd9d637 100644
--- a/crates/ui-egui/src/i18n/de.tsv
+++ b/crates/ui-egui/src/i18n/de.tsv
@@ -2603,6 +2603,7 @@ mark-style	Japanese	Japanisch
 	Repeat Tab	Tabulator wiederholen
 	Repeat {name}	{name} wiederholen
 	Replace	Ersetzen
+	Replace:	Ersetzen:
 	Replace Font	Schrift ersetzen
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Ersetzen Sie sie durch eine andere Datei oder ignorieren Sie sie: Ihre Bilder zeigen weiterhin die mit dem Dokument gespeicherte Vorschau.
 	Replace Spine	Achse ersetzen
diff --git a/crates/ui-egui/src/i18n/el.tsv b/crates/ui-egui/src/i18n/el.tsv
index 0b3fbeb45..b40a460de 100644
--- a/crates/ui-egui/src/i18n/el.tsv
+++ b/crates/ui-egui/src/i18n/el.tsv
@@ -1798,6 +1798,7 @@ font-technology	Variable	Μεταβλητές
 	Rename	Μετονομασία
 	Repeat	Επανάληψη
 	Replace	Αντικατάσταση
+	Replace:	Αντικατάσταση:
 	Replace…	Αντικατάσταση…
 	Reselect	Επαναφορά προηγούμενης επιλογής
 	Reset	Επαναφορά
diff --git a/crates/ui-egui/src/i18n/es.tsv b/crates/ui-egui/src/i18n/es.tsv
index b47bae620..72b330091 100644
--- a/crates/ui-egui/src/i18n/es.tsv
+++ b/crates/ui-egui/src/i18n/es.tsv
@@ -2641,6 +2641,7 @@ font-technology	Variable	Variables
 	Repeat Tab	Repetir tabulación
 	Repeat {name}	Repetir {name}
 	Replace	Reemplazar
+	Replace:	Reemplazar:
 	Replace Font	Reemplazar fuente
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Reemplázalo con otro archivo o ignóralo: sus imágenes seguirán mostrando la vista previa guardada con el documento.
 	Replace Spine	Reemplazar eje
diff --git a/crates/ui-egui/src/i18n/fi.tsv b/crates/ui-egui/src/i18n/fi.tsv
index 5c04f9d8d..62b0820c7 100644
--- a/crates/ui-egui/src/i18n/fi.tsv
+++ b/crates/ui-egui/src/i18n/fi.tsv
@@ -3720,6 +3720,7 @@ axis	Both	Molemmat
 	Set Text	Aseta teksti
 	Insert Character	Lisää merkki
 	Replace	Korvaa
+	Replace:	Korvaa:
 	Type on a Path Options	Polulla olevan tekstin asetukset
 	Highlight Variable	Korosta muuttuja
 	New Variable	Uusi muuttuja
diff --git a/crates/ui-egui/src/i18n/fr.tsv b/crates/ui-egui/src/i18n/fr.tsv
index 09381076c..0c9ddfc3d 100644
--- a/crates/ui-egui/src/i18n/fr.tsv
+++ b/crates/ui-egui/src/i18n/fr.tsv
@@ -2638,6 +2638,7 @@ font-technology	Variable	Variables
 	Repeat Tab	Répéter la tabulation
 	Repeat {name}	Répéter {name}
 	Replace	Remplacer
+	Replace:	Remplacer :
 	Replace Font	Remplacer la police
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Remplacez-le par un autre fichier ou ignorez-le : ses images continueront d’afficher l’aperçu enregistré avec le document.
 	Replace Spine	Remplacer la dorsale
diff --git a/crates/ui-egui/src/i18n/hu.tsv b/crates/ui-egui/src/i18n/hu.tsv
index 97da7b1e7..4b6adc0ea 100644
--- a/crates/ui-egui/src/i18n/hu.tsv
+++ b/crates/ui-egui/src/i18n/hu.tsv
@@ -3169,6 +3169,7 @@ mark-style	Japanese	Japán
 	Repeat Tab	Tabulátor ismétlése
 	Repeat {name}	Ismétlés: {name}
 	Replace	Csere
+	Replace:	Csere:
 	Replace Font	Betűtípus cseréje
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Cseréld le egy másik fájlra, vagy hagyd ki: a képei a dokumentummal mentett előnézetet mutatják tovább.
 	Replace Spine	Gerinc cseréje
diff --git a/crates/ui-egui/src/i18n/id.tsv b/crates/ui-egui/src/i18n/id.tsv
index e58b45121..752637084 100644
--- a/crates/ui-egui/src/i18n/id.tsv
+++ b/crates/ui-egui/src/i18n/id.tsv
@@ -3537,6 +3537,7 @@ axis	Both	Keduanya
 	Set Text	Atur teks
 	Insert Character	Sisipkan karakter
 	Replace	Ganti
+	Replace:	Ganti:
 	Type on a Path Options	Opsi teks pada jalur
 	Highlight Variable	Sorot variabel
 	New Variable	Variabel baru
diff --git a/crates/ui-egui/src/i18n/it.tsv b/crates/ui-egui/src/i18n/it.tsv
index 7ad8c5e39..4e27d545a 100644
--- a/crates/ui-egui/src/i18n/it.tsv
+++ b/crates/ui-egui/src/i18n/it.tsv
@@ -2672,6 +2672,7 @@ mark-style	Japanese	Giapponese
 	Repeat Tab	Ripeti tabulazione
 	Repeat {name}	Ripeti {name}
 	Replace	Sostituisci
+	Replace:	Sostituisci:
 	Replace Font	Sostituisci font
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Sostituiscilo con un altro file oppure ignoralo: le sue immagini continueranno a mostrare l'anteprima salvata con il documento.
 	Replace Spine	Sostituisci dorsale
diff --git a/crates/ui-egui/src/i18n/ja.tsv b/crates/ui-egui/src/i18n/ja.tsv
index 2cf6eafe8..bc8c797ff 100644
--- a/crates/ui-egui/src/i18n/ja.tsv
+++ b/crates/ui-egui/src/i18n/ja.tsv
@@ -2652,6 +2652,7 @@ mark-style	Japanese	日本式
 	Repeat Tab	タブを繰り返し
 	Repeat {name}	{name}を繰り返す
 	Replace	置換
+	Replace:	置換:
 	Replace Font	フォントを置換
 	Replace Symbol	シンボルを置き換え
 	Replace With Font	置換するフォント
diff --git a/crates/ui-egui/src/i18n/ka.tsv b/crates/ui-egui/src/i18n/ka.tsv
index d2d6669b3..20db589b7 100644
--- a/crates/ui-egui/src/i18n/ka.tsv
+++ b/crates/ui-egui/src/i18n/ka.tsv
@@ -3322,6 +3322,7 @@ axis	Both	ორივე
 	Set Text	ტექსტის დაყენება
 	Insert Character	სიმბოლოს ჩასმა
 	Replace	ჩანაცვლება
+	Replace:	ჩანაცვლება:
 	Type on a Path Options	ტრაექტორიაზე ტექსტის პარამეტრები
 	Highlight Variable	ცვლადის გამოკვეთა
 	New Variable	ახალი ცვლადი
diff --git a/crates/ui-egui/src/i18n/ko.tsv b/crates/ui-egui/src/i18n/ko.tsv
index 3ba2c74ea..266bbc0e7 100644
--- a/crates/ui-egui/src/i18n/ko.tsv
+++ b/crates/ui-egui/src/i18n/ko.tsv
@@ -2639,6 +2639,7 @@ mark-style	Japanese	일본식
 	Repeat Tab	탭 반복
 	Repeat {name}	{name} 반복
 	Replace	바꾸기
+	Replace:	바꾸기:
 	Replace Font	글꼴 바꾸기
 	Replace Symbol	심볼 바꾸기
 	Replace With Font	바꿀 글꼴
diff --git a/crates/ui-egui/src/i18n/nl.tsv b/crates/ui-egui/src/i18n/nl.tsv
index 318126cbf..7080aa48a 100644
--- a/crates/ui-egui/src/i18n/nl.tsv
+++ b/crates/ui-egui/src/i18n/nl.tsv
@@ -3551,6 +3551,7 @@ axis	Both	Beide
 	Set Text	Tekst instellen
 	Insert Character	Teken invoegen
 	Replace	Vervangen
+	Replace:	Vervangen:
 	Type on a Path Options	Opties voor tekst op pad
 	Highlight Variable	Variabele markeren
 	New Variable	Nieuwe variabele
diff --git a/crates/ui-egui/src/i18n/pl.tsv b/crates/ui-egui/src/i18n/pl.tsv
index 8cf23270b..56fb73b65 100644
--- a/crates/ui-egui/src/i18n/pl.tsv
+++ b/crates/ui-egui/src/i18n/pl.tsv
@@ -3642,6 +3642,7 @@ axis	Both	Obie
 	Set Text	Ustaw tekst
 	Insert Character	Wstaw znak
 	Replace	Zastąp
+	Replace:	Zastąp:
 	Type on a Path Options	Opcje tekstu na ścieżce
 	Highlight Variable	Wyróżnij zmienną
 	New Variable	Nowa zmienna
diff --git a/crates/ui-egui/src/i18n/pt-br.tsv b/crates/ui-egui/src/i18n/pt-br.tsv
index c698419f1..91217099c 100644
--- a/crates/ui-egui/src/i18n/pt-br.tsv
+++ b/crates/ui-egui/src/i18n/pt-br.tsv
@@ -2179,6 +2179,7 @@
 	Repeat Tab	Repetir Parada de Tabulação
 	Repeat {name}	Repetir {name}
 	Replace	Substituir
+	Replace:	Substituir:
 	Replace Font	Substituir Fonte
 	Replace Spine	Substituir Coluna
 	Replace Symbol	Substituir Símbolo
diff --git a/crates/ui-egui/src/i18n/ru.tsv b/crates/ui-egui/src/i18n/ru.tsv
index 7db0f6a50..48d428b20 100644
--- a/crates/ui-egui/src/i18n/ru.tsv
+++ b/crates/ui-egui/src/i18n/ru.tsv
@@ -2668,6 +2668,7 @@ mark-style	Japanese	Японский
 	Repeat Tab	Повторить табуляцию
 	Repeat {name}	Повторить {name}
 	Replace	Заменить
+	Replace:	Заменить:
 	Replace Font	Заменить шрифт
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Замените его другим файлом или игнорируйте: его изображения продолжат показывать предварительный просмотр, сохранённый с документом.
 	Replace Spine	Заменить остов
diff --git a/crates/ui-egui/src/i18n/sv.tsv b/crates/ui-egui/src/i18n/sv.tsv
index d5e0c7c23..27bf1d75a 100644
--- a/crates/ui-egui/src/i18n/sv.tsv
+++ b/crates/ui-egui/src/i18n/sv.tsv
@@ -2583,6 +2583,7 @@ font-technology	Variable	Variabla
 	Repeat Tab	Upprepa tabb
 	Repeat {name}	Upprepa {name}
 	Replace	Ersätt
+	Replace:	Ersätt:
 	Replace Font	Ersätt typsnitt
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Ersätt den med en annan fil eller ignorera den: dess bilder fortsätter att visa förhandsgranskningen som sparats med dokumentet.
 	Replace Spine	Ersätt ryggrad
diff --git a/crates/ui-egui/src/i18n/tr.tsv b/crates/ui-egui/src/i18n/tr.tsv
index d3566fbd8..7c7cc5ec8 100644
--- a/crates/ui-egui/src/i18n/tr.tsv
+++ b/crates/ui-egui/src/i18n/tr.tsv
@@ -2460,6 +2460,7 @@ shape	Open	Açık
 	Repeat Tab	Sekmeyi Tekrarla
 	Repeat {name}	{name}'yi tekrarla
 	Replace	Değiştir
+	Replace:	Değiştir:
 	Replace Font	Yazı Tipini Değiştir
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Onu başka bir dosyayla değiştirin veya yok sayın: resimleri, belgeyle birlikte kaydedilen önizlemeyi göstermeye devam eder.
 	Replace Spine	Omurgayı Değiştir
diff --git a/crates/ui-egui/src/i18n/uk.tsv b/crates/ui-egui/src/i18n/uk.tsv
index 1aec37d5f..217fad075 100644
--- a/crates/ui-egui/src/i18n/uk.tsv
+++ b/crates/ui-egui/src/i18n/uk.tsv
@@ -2664,6 +2664,7 @@ mark-style	Japanese	Японський
 	Repeat Tab	Повторити табуляцію
 	Repeat {name}	Повторити {name}
 	Replace	Замінити
+	Replace:	Замінити:
 	Replace Font	Замінити шрифт
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Замініть його іншим файлом або ігноруйте: зображення продовжать показувати попередній перегляд, збережений з документом.
 	Replace Spine	Замінити вісь
diff --git a/crates/ui-egui/src/i18n/vi.tsv b/crates/ui-egui/src/i18n/vi.tsv
index 205fac49c..f30176f57 100644
--- a/crates/ui-egui/src/i18n/vi.tsv
+++ b/crates/ui-egui/src/i18n/vi.tsv
@@ -2935,6 +2935,7 @@ mark-style	Japanese	Kiểu Nhật
 	Repeat Tab	Tab lặp lại
 	Repeat {name}	Lặp lại {name}
 	Replace	Thay thế
+	Replace:	Thay thế:
 	Replace Font	Thay thế phông chữ
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	Thay thế bằng tệp khác hoặc bỏ qua: ảnh của nó vẫn hiển thị bản xem trước đã lưu cùng tài liệu.
 	Replace Spine	Thay thế trục
diff --git a/crates/ui-egui/src/i18n/zh-hans.tsv b/crates/ui-egui/src/i18n/zh-hans.tsv
index 49ee6d305..4b241917d 100644
--- a/crates/ui-egui/src/i18n/zh-hans.tsv
+++ b/crates/ui-egui/src/i18n/zh-hans.tsv
@@ -2541,6 +2541,7 @@ font-script	Japanese	汉字
 	Repeat Tab	重复制表位
 	Repeat {name}	重复 {name}
 	Replace	替换
+	Replace:	替换：
 	Replace Font	替换字体
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	将其替换为其他文件，或忽略：其图像继续显示随文档保存的预览。
 	Replace Spine	替换脊线
diff --git a/crates/ui-egui/src/i18n/zh-hant.tsv b/crates/ui-egui/src/i18n/zh-hant.tsv
index c957c07ee..98026e0fb 100644
--- a/crates/ui-egui/src/i18n/zh-hant.tsv
+++ b/crates/ui-egui/src/i18n/zh-hant.tsv
@@ -3478,6 +3478,7 @@ font-script	Japanese	漢字
 	Repeat Tab	重複定位點
 	Repeat {name}	重複 {name}
 	Replace	取代
+	Replace:	取代：
 	Replace Font	取代字體
 	Replace it with another file, or ignore it: its images keep showing the preview saved with the document.	以其他檔案取代，或忽略：其影像會繼續顯示隨文件儲存的預覽。
 	Replace Spine	取代脊線
diff --git a/crates/ui-egui/src/panels/symbols.rs b/crates/ui-egui/src/panels/symbols.rs
index 0bd815c0d..e99a24bf6 100644
--- a/crates/ui-egui/src/panels/symbols.rs
+++ b/crates/ui-egui/src/panels/symbols.rs
@@ -149,6 +149,41 @@ fn has_instances_selected(app: &VectorcraftApp) -> bool {
     })
 }
 
+/// The symbols of the selected objects when every one is a symbol instance; `None` otherwise.
+fn selected_instance_symbols(app: &VectorcraftApp) -> Option<Vec<String>> {
+    let st = app.session.active()?;
+    let symbols: Option<Vec<String>> = st
+        .selection
+        .objects
+        .iter()
+        .map(|id| match st.doc.node(*id).map(|n| &n.kind) {
+            Some(NodeKind::SymbolInstance { symbol, .. }) => Some(symbol.clone()),
+            _ => None,
+        })
+        .collect();
+    symbols.filter(|s| !s.is_empty())
+}
+
+/// The Control bar's Replace menu while symbol instances alone are selected: the document's
+/// symbols, showing the one the instances share (blank when they differ); picking another
+/// replaces them all, as "Select a new symbol from the Replace dropdown in the Control panel"
+/// (<https://helpx.adobe.com/illustrator/desktop/manage-objects/traces-mockups-symbols/edit-symbols.html>).
+pub(crate) fn control_bar(app: &mut VectorcraftApp, ui: &mut Ui) {
+    let Some(symbols) = selected_instance_symbols(app) else { return };
+    let Some(st) = app.session.active() else { return };
+    let names: Vec<String> = st.doc.symbols.iter().map(|s| s.name.clone()).collect();
+    let shared = symbols.first().filter(|first| symbols.iter().all(|s| s == *first)).cloned().unwrap_or_default();
+    ui.label(egui::RichText::new(tl!("Replace:")).size(12.0).color(Tokens::get(ui.ctx()).text));
+    let options: Vec<&str> = names.iter().map(String::as_str).collect();
+    if let Some(name) = widgets::dropdown_names(ui, "cb-symbol-replace", &shared, &options, 140.0).and_then(|i| names.get(i))
+        && *name != shared
+        && let Err(e) = app.run("symbol.replace", json!({ "name": name }))
+    {
+        app.status(e);
+    }
+    ui.add_space(4.0);
+}
+
 pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
     let t = Tokens::get(ui.ctx());
     let Some((doc, keys)) = app.session.active().map(|d| (d.doc.clone(), document_symbols(d))) else { return };
@@ -702,4 +737,65 @@ mod tests {
         };
         assert!(orange(3, 3) && orange(36, 36), "{:?} {:?}", thumb.pixels[3 * 40 + 3], thumb.pixels[36 * 40 + 36]);
     }
+
+    /// #4121: with symbol instances selected, the Control bar's Replace menu lists the document's
+    /// symbols and shows the instance's own; picking another replaces it.
+    #[test]
+    fn the_control_bar_replace_menu_swaps_the_selected_instances_symbol() {
+        fn bar(app: &mut VectorcraftApp, ctx: &egui::Context, events: Vec<egui::Event>) -> Vec<egui::Shape> {
+            let raw = egui::RawInput { screen_rect: Some(Rect::from_min_size(Pos2::ZERO, vec2(800.0, 400.0))), events, ..Default::default() };
+            let mut out = ctx.run_ui(raw, |ui| {
+                ui.horizontal(|ui| control_bar(app, ui));
+            });
+            out.textures_delta.clear();
+            out.shapes.into_iter().map(|c| c.shape).collect()
+        }
+        fn text_at(shapes: &[egui::Shape], s: &str) -> Option<Pos2> {
+            shapes.iter().find_map(|sh| match sh {
+                egui::Shape::Text(t) if t.galley.text().trim() == s => Some(t.visual_bounding_rect().center()),
+                egui::Shape::Vec(v) => text_at(v, s),
+                _ => None,
+            })
+        }
+        fn click(app: &mut VectorcraftApp, ctx: &egui::Context, at: Pos2) {
+            bar(app, ctx, vec![egui::Event::PointerMoved(at), button(at, true)]);
+            bar(app, ctx, vec![button(at, false)]);
+        }
+        let mut app = VectorcraftApp::new(Session::new(), Default::default());
+        app.run("file.new", json!({"width": 300, "height": 200})).unwrap();
+        for (name, x) in [("Leaf", 10), ("Star", 150)] {
+            app.run("shape.rectangle", json!({"x": x, "y": 10, "width": 30, "height": 30})).unwrap();
+            app.run("symbol.new", json!({"name": name})).unwrap();
+        }
+        let instance_of = |app: &VectorcraftApp, name: &str| {
+            let mut found = None;
+            for l in &app.session.active().unwrap().doc.layers {
+                l.walk(&mut |n| {
+                    if let NodeKind::SymbolInstance { symbol, .. } = &n.kind
+                        && symbol == name
+                    {
+                        found = Some(n.id);
+                    }
+                });
+            }
+            found
+        };
+        let leaf = instance_of(&app, "Leaf").expect("a Leaf instance");
+        let ctx = egui::Context::default();
+        crate::theme::install_fonts(&ctx);
+        // Art, not an instance: no Replace menu.
+        let rect = app.run("shape.rectangle", json!({"x": 10, "y": 100, "width": 30, "height": 30})).unwrap()["id"].as_u64().unwrap();
+        app.run("select.set", json!({"ids": [rect]})).unwrap();
+        assert!(text_at(&bar(&mut app, &ctx, vec![]), "Replace:").is_none());
+        app.run("select.set", json!({"ids": [leaf.0]})).unwrap();
+        bar(&mut app, &ctx, vec![]);
+        let shapes = bar(&mut app, &ctx, vec![]);
+        assert!(text_at(&shapes, "Replace:").is_some());
+        let shown = text_at(&shapes, "Leaf").expect("the menu shows the instance's symbol");
+        click(&mut app, &ctx, shown);
+        let star = text_at(&bar(&mut app, &ctx, vec![]), "Star").expect("the menu lists the other symbol");
+        click(&mut app, &ctx, star);
+        let doc = &app.session.active().unwrap().doc;
+        assert!(matches!(&doc.node(leaf).unwrap().kind, NodeKind::SymbolInstance { symbol, .. } if symbol == "Star"), "the instance is replaced");
+    }
 }
diff --git a/docs/ui-parity.md b/docs/ui-parity.md
index 0dafd6bab..f9d9df3a7 100644
--- a/docs/ui-parity.md
+++ b/docs/ui-parity.md
@@ -1,6 +1,6 @@
 # UI and interaction parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Color Mixer popover: the Color panel's menu with its color modes (#4249); scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (Control bar: a Replace menu swaps the selected symbol instances' symbol (#4121); scores unchanged) · **Target:** Adobe Illustrator 2026 (30.x)
 
 ## Feature submission evidence
 
@@ -361,6 +361,7 @@ separate. Scores and hours unchanged. [Behavior and command details](development
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-30 | minor | Control bar: a Replace menu swaps the selected symbol instances' symbol (#4121); scores and estimates unchanged |
 | 2026-10-30 | minor | Color Mixer popover: the Color panel's menu with its color modes (#4249); scores and estimates unchanged |
 | 2026-10-30 | minor | Object › Path › Average & Join… (`path.averageJoin`, Cmd+Alt+Shift+J) moves two open path ends to their midpoint and joins them there, the joined anchor a corner or a smooth point as its dialog's Points choice asks, in one undo step; one row done; scores and estimates unchanged. |
 | 2026-10-30 | minor | G12: Preferences audit (#394): 5 options are stored but not acted on (Open Documents As Tabs, Units › East Asian Type, Hyphenation › Default Language, Scratch Disks, Legacy vector clipboard), each waiting on a subsystem; Highlight Alternate Glyphs, Real-time Drawing and the Devices options act; scores and estimates unchanged |