diff --git a/ROADMAP.md b/ROADMAP.md
index 3d1a1d0d8..328b92f40 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~25 points of "ready for real work" and ~160–240 h away
 
-> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-25 · **Change:** minor (AutoSum over a selected row puts its total to the right, and fills a selection's empty last row and column; earlier: macro engine and `macro.*` commands; macro interface on the Automate tab) · **Target:** Microsoft Excel (Microsoft 365)
+> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-31 · **Change:** minor (Formulas › Function Library as labelled buttons with category menus; earlier: AutoSum over a selected row puts its total to the right, and fills a selection's empty last row and column) · **Target:** Microsoft Excel (Microsoft 365)
 
 GridCraft aims at full Microsoft Excel parity, and at being better in places: faster, open (XLSX
 is the native format), fully scriptable by agents (MCP, control channel, CLI), and on the web.
@@ -135,6 +135,7 @@ Ranked; estimates in Opus 5.5 agent-hours. Detail and the full beta-gate list in
 
 | Date | What landed |
 |---|---|
+| 2026-10-31 | Formulas › Function Library as a big Insert Function button, the AutoSum split button and three columns of labelled small buttons, each category book in its own colour; category menus end with Insert Function… on that category; More Functions cascades into the remaining categories; Home › Editing shares the AutoSum menu; the MR key tip opens Recently Used |
 | 2026-10-25 | AutoSum over a selection does what Excel does: a selected row gets one total to its right (in its last cell if that is empty), not a one-cell total under each cell; a block whose last column is empty gets each row's total there, one whose last row is empty each column's, and with both the corner gets the total of the block; otherwise totals go under each column as before |
 | 2026-10-24 | Macro interface ([macros.md](docs/macros.md#in-the-window)): an Automate › Macros group (Record Macro, which turns into Stop Recording, Use Relative References, Run Macro with recent macros); "Recording · N steps" with Stop in the status bar; a Record Macro dialog (checked name, free Ctrl+Shift shortcut, description); the Macros dialog lists macros beside Automate scripts and a VBA project, with Run, Step Into, Edit, Create, Delete and Options; Ctrl+Shift+letter macro shortcuts; questions that offer Run, Overwrite, Shift Down or Shift Right; a step editor with a breakpoint gutter, drag to reorder, a command picker, reference boxes that switch between relative tokens and absolute references, Inputs and Output tabs, a debug bar (Check, Run, Step, Continue, Run to Here, Stop with keep or undo) and grid overlays for inputs, writes, conflicts and the current step |
 | 2026-10-24 | Go To lists the named ranges of every sheet (`Sheet2!Name` for a name scoped to another sheet; hidden names, constants and formulas left out) and the references entered before, a double-click goes to an entry, and the Reference box takes several names or references separated by commas (`Price, Type`, `B14:C22,F19:G30`) |
@@ -244,6 +245,7 @@ Ranked; estimates in Opus 5.5 agent-hours. Detail and the full beta-gate list in
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-31 | minor | Progress log: Function Library |
 | 2026-10-25 | minor | Progress log: AutoSum over a selected row, and a selection's empty last row and column |
 | 2026-10-24 | minor | Macro interface on the Automate tab; progress log row |
 | 2026-10-24 | minor | Macro engine and `macro.*` commands; catalog 275 / 291 → 276 / 292 (View › Macros › Record Macro); progress log row |
diff --git a/crates/ui-egui/src/dialogs.rs b/crates/ui-egui/src/dialogs.rs
index 92187d5c0..df166e229 100644
--- a/crates/ui-egui/src/dialogs.rs
+++ b/crates/ui-egui/src/dialogs.rs
@@ -853,7 +853,11 @@ impl Dialog {
                 }
                 d
             }
-            "insertFunction" => Dialog::custom("insertFunction", "Formula Builder", json!({"category": "Most Recently Used"})),
+            "insertFunction" => {
+                // A Function Library menu opens it on its own category.
+                let category = p("category").as_str().unwrap_or(crate::function_library::MOST_RECENTLY_USED).to_string();
+                Dialog::custom("insertFunction", "Formula Builder", json!({"category": category}))
+            }
             "find" => {
                 let mut d = Dialog::custom("find", "Find and Replace", json!({"what": "", "with": "", "within": "sheet", "lookIn": "formulas"}));
                 d.tab = if p("replace").as_bool() == Some(true) { "Replace".into() } else { "Find".into() };
diff --git a/crates/ui-egui/src/dialogs/insert_function.rs b/crates/ui-egui/src/dialogs/insert_function.rs
index b662d7197..2f922d644 100644
--- a/crates/ui-egui/src/dialogs/insert_function.rs
+++ b/crates/ui-egui/src/dialogs/insert_function.rs
@@ -26,7 +26,7 @@ pub(super) fn insert_function(app: &mut SheetApp, ui: &mut egui::Ui, d: &mut Dia
     egui::ScrollArea::vertical().max_height(260.0).show(ui, |ui| {
         for (i, f) in hits.iter().enumerate() {
             let name = locale.function_name(f["name"].as_str().unwrap_or(""));
-            let category = language.tr(function_category_label(f["category"].as_str().unwrap_or("")));
+            let category = language.tr(crate::function_library::category_label(f["category"].as_str().unwrap_or("")));
             let r = ui.add(egui::Button::selectable(i == d.list_index, format!("{name:<18} {category}")).min_size(vec2(480.0, 20.0)));
             if r.clicked() {
                 d.list_index = i;
@@ -58,15 +58,3 @@ pub(super) fn insert_function(app: &mut SheetApp, ui: &mut egui::Ui, d: &mut Dia
         *confirm = true;
     }
 }
-
-/// Excel's name for a function category, given the catalog's id (`MathTrig`).
-fn function_category_label(id: &str) -> &str {
-    match id {
-        "DateTime" => "Date & Time",
-        "Lookup" => "Lookup & Reference",
-        "MathTrig" => "Math & Trig",
-        "AddIn" => "Add-in and Automation",
-        // Financial, Logical, Text, Statistical, Engineering, Database, Information, …
-        other => other,
-    }
-}
diff --git a/crates/ui-egui/src/function_library.rs b/crates/ui-egui/src/function_library.rs
new file mode 100644
index 000000000..434f4a6ac
--- /dev/null
+++ b/crates/ui-egui/src/function_library.rs
@@ -0,0 +1,191 @@
+//! The Formulas tab's Function Library: the function categories, their menus, the AutoSum menu
+//! (shared with Home › Editing), and the Recently Used menu, which lists what the engine's
+//! `formulas.recentlyUsed` returns.
+
+use std::sync::OnceLock;
+
+use egui::{Ui, vec2};
+use serde_json::json;
+
+use crate::SheetApp;
+
+/// The Insert Function category that lists [`recent`].
+pub const MOST_RECENTLY_USED: &str = "Most Recently Used";
+/// The Insert Function category that lists every function.
+pub const ALL: &str = "All";
+
+/// The function categories in the order the Insert Function dialog lists them: (the engine's
+/// category id, the label people see).
+pub const CATEGORIES: [(&str, &str); 14] = [
+    ("Financial", "Financial"),
+    ("DateTime", "Date & Time"),
+    ("MathTrig", "Math & Trig"),
+    ("Statistical", "Statistical"),
+    ("Lookup", "Lookup & Reference"),
+    ("Database", "Database"),
+    ("Text", "Text"),
+    ("Logical", "Logical"),
+    ("Information", "Information"),
+    ("Engineering", "Engineering"),
+    ("Cube", "Cube"),
+    ("Compatibility", "Compatibility"),
+    ("Web", "Web"),
+    ("AddIn", "Add-in and Automation"),
+];
+
+/// The categories under More Functions, each a cascading submenu.
+pub const MORE_FUNCTIONS: [&str; 6] = ["Statistical", "Engineering", "Cube", "Information", "Compatibility", "Web"];
+
+/// The label of an engine category id (the id itself if it is unknown).
+pub fn category_label(id: &str) -> &str {
+    CATEGORIES.iter().find(|(c, _)| *c == id).map(|(_, l)| *l).unwrap_or(id)
+}
+
+/// The engine category id for a category given by id or label, in any case.
+pub fn category_id(name: &str) -> Option<&'static str> {
+    CATEGORIES.iter().find(|(c, l)| c.eq_ignore_ascii_case(name) || l.eq_ignore_ascii_case(name)).map(|(c, _)| *c)
+}
+
+/// One function of the library.
+#[derive(Clone, Debug)]
+pub struct FnEntry {
+    pub name: String,
+    pub category: String,
+    pub description: String,
+}
+
+/// Every function, sorted by name (built once; the list is static).
+pub fn all() -> &'static [FnEntry] {
+    static LIST: OnceLock<Vec<FnEntry>> = OnceLock::new();
+    LIST.get_or_init(|| {
+        let mut list: Vec<FnEntry> = gridcraft_engine::cmd::formulas::function_list()
+            .iter()
+            .filter_map(|f| {
+                Some(FnEntry {
+                    name: f["name"].as_str()?.to_string(),
+                    category: f["category"].as_str().unwrap_or("").to_string(),
+                    description: f["description"].as_str().unwrap_or("").to_string(),
+                })
+            })
+            .collect();
+        list.sort_by(|a, b| a.name.cmp(&b.name));
+        list.dedup_by(|a, b| a.name == b.name);
+        list
+    })
+}
+
+/// The function named `name` (upper case), if the library knows it.
+pub fn find(name: &str) -> Option<&'static FnEntry> {
+    let list = all();
+    list.binary_search_by(|f| f.name.as_str().cmp(name)).ok().and_then(|i| list.get(i))
+}
+
+/// The functions of one engine category, in name order.
+pub fn in_category(id: &str) -> impl Iterator<Item = &'static FnEntry> + '_ {
+    all().iter().filter(move |f| f.category == id)
+}
+
+/// The name a function shows under in the interface language.
+fn display_name<'a>(app: &SheetApp, name: &'a str) -> &'a str {
+    let locale = app.ui.language.formula_locale();
+    app.session.active().map(|d| crate::formula_locale::completion_name(name, locale, &d.wb, d.wb.active_sheet())).unwrap_or(name)
+}
+
+/// One menu row per function, with its description on hover; a click starts the formula.
+fn function_items<'a>(app: &mut SheetApp, ui: &mut Ui, names: impl Iterator<Item = &'a str>) {
+    let language = app.ui.language;
+    let locale = language.formula_locale();
+    ui.set_max_height(420.0);
+    egui::ScrollArea::vertical().max_height(380.0).show(ui, |ui| {
+        for n in names {
+            let Some(entry) = find(n) else { continue };
+            let name = display_name(app, &entry.name);
+            let r = ui.add(egui::Button::new(name).frame(false).min_size(vec2(180.0, 20.0)));
+            // The description is looked up only while the row is hovered.
+            let r = r.on_hover_ui(|ui| {
+                ui.label(crate::formula_locale::description(&entry.name, locale, language).unwrap_or_default());
+            });
+            if r.clicked() {
+                app.run_or_alert("formulas.insertFunction", json!({"name": entry.name}));
+                ui.close();
+            }
+        }
+    });
+}
+
+/// The "Insert Function…" row that ends every category menu; it opens the dialog on `category`.
+fn insert_function_item(app: &mut SheetApp, ui: &mut Ui, category: &str) {
+    ui.separator();
+    let label = app.ui.language.tr("Insert Function…");
+    if ui.add(egui::Button::new(label).frame(false).min_size(vec2(180.0, 22.0))).clicked() {
+        app.open_dialog("insertFunction", json!({"category": category}));
+        ui.close();
+    }
+}
+
+/// The menu of one category: its functions, then Insert Function….
+pub fn category_menu(app: &mut SheetApp, ui: &mut Ui, id: &str) {
+    let names: Vec<&str> = in_category(id).map(|f| f.name.as_str()).collect();
+    function_items(app, ui, names.into_iter());
+    insert_function_item(app, ui, category_label(id));
+}
+
+/// The functions `formulas.recentlyUsed` lists, newest first (none without a workbook).
+pub fn recent(app: &mut SheetApp) -> Vec<String> {
+    let list = app.session.execute("formulas.recentlyUsed", json!({})).unwrap_or_default();
+    list.as_array().map(|a| a.iter().filter_map(|n| n.as_str().map(String::from)).collect()).unwrap_or_default()
+}
+
+/// Recently Used: the most recent functions, newest first, then Insert Function….
+pub fn recent_menu(app: &mut SheetApp, ui: &mut Ui) {
+    let recent = recent(app);
+    function_items(app, ui, recent.iter().map(String::as_str));
+    insert_function_item(app, ui, MOST_RECENTLY_USED);
+}
+
+/// More Functions: a cascading submenu per remaining category.
+pub fn more_menu(app: &mut SheetApp, ui: &mut Ui) {
+    for id in MORE_FUNCTIONS {
+        let label = app.ui.language.tr(category_label(id)).to_string();
+        ui.menu_button(label, |ui| category_menu(app, ui, id));
+    }
+}
+
+/// The AutoSum menu, shared by Home › Editing and Formulas › Function Library: a function, or
+/// the Insert Function dialog.
+pub fn auto_sum_menu(app: &mut SheetApp, ui: &mut Ui) {
+    for (label, f) in [("Sum", "SUM"), ("Average", "AVERAGE"), ("Count Numbers", "COUNT"), ("Max", "MAX"), ("Min", "MIN")] {
+        let label = app.ui.language.tr(label);
+        if ui.add(egui::Button::new(label).frame(false).min_size(vec2(160.0, 22.0))).clicked() {
+            app.run_or_alert("formulas.autoSum", json!({"function": f}));
+            ui.close();
+        }
+    }
+    ui.separator();
+    let label = app.ui.language.tr("More Functions…");
+    if ui.add(egui::Button::new(label).frame(false).min_size(vec2(160.0, 22.0))).clicked() {
+        app.open_dialog("insertFunction", json!({}));
+        ui.close();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn categories_cover_every_function() {
+        for f in all() {
+            assert!(category_id(&f.category).is_some(), "{} is in an unknown category {}", f.name, f.category);
+        }
+        assert_eq!(category_id("date & time"), Some("DateTime"));
+        assert_eq!(category_id("Lookup"), Some("Lookup"));
+        assert_eq!(category_id("nope"), None);
+        for c in MORE_FUNCTIONS {
+            assert!(category_id(c).is_some());
+        }
+        assert!(all().windows(2).all(|w| w[0].name < w[1].name), "sorted by name, without duplicates");
+        assert_eq!(find("SUM").map(|f| f.category.as_str()), Some("MathTrig"));
+        assert!(find("NOT_A_FUNCTION").is_none());
+    }
+}
diff --git a/crates/ui-egui/src/i18n/cs.rs b/crates/ui-egui/src/i18n/cs.rs
index 9a6d54030..3ba6cb732 100644
--- a/crates/ui-egui/src/i18n/cs.rs
+++ b/crates/ui-egui/src/i18n/cs.rs
@@ -417,11 +417,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Dlouhé datum",
         "More Number Formats…" => "Další formáty čísel…",
         "Financial" => "Finanční",
+        "Recently Used" => "Naposledy použité",
         "Logical" => "Logické",
-        "Date &\nTime" => "Datum a\nčas",
-        "Lookup &\nReference" => "Vyhledávání\na odkazy",
-        "Math &\nTrig" => "Matematika a\ntrigonometrie",
-        "More\nFunctions" => "Další\nfunkce",
+        "Date & Time" => "Datum a čas",
+        "Lookup & Reference" => "Vyhledávání a odkazy",
+        "Math & Trig" => "Matematika a trigonometrie",
+        "More Functions" => "Další funkce",
         "Sheet Options|View" => "Zobrazit",
         "Print" => "Tisknout",
         "Print What" => "Co tisknout",
diff --git a/crates/ui-egui/src/i18n/de.rs b/crates/ui-egui/src/i18n/de.rs
index 6427b279d..420214ffb 100644
--- a/crates/ui-egui/src/i18n/de.rs
+++ b/crates/ui-egui/src/i18n/de.rs
@@ -420,11 +420,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Langes Datum",
         "More Number Formats…" => "Weitere Zahlenformate…",
         "Financial" => "Finanzmathematik",
+        "Recently Used" => "Zuletzt verwendet",
         "Logical" => "Logisch",
-        "Date &\nTime" => "Datum &\nUhrzeit",
-        "Lookup &\nReference" => "Nachschlagen &\nVerweisen",
-        "Math &\nTrig" => "Mathematik &\nTrigonometrie",
-        "More\nFunctions" => "Weitere\nFunktionen",
+        "Date & Time" => "Datum & Uhrzeit",
+        "Lookup & Reference" => "Nachschlagen & Verweisen",
+        "Math & Trig" => "Mathematik & Trigonometrie",
+        "More Functions" => "Weitere Funktionen",
         "Page Layout|Orientation" => "Seitenausrichtung",
         "Display theme" => "Anzeigedesign",
         "System" => "System",
diff --git a/crates/ui-egui/src/i18n/el.rs b/crates/ui-egui/src/i18n/el.rs
index 9231f8244..165d94cd8 100644
--- a/crates/ui-egui/src/i18n/el.rs
+++ b/crates/ui-egui/src/i18n/el.rs
@@ -389,10 +389,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Περισσότερες μορφές αριθμών…",
         "Financial" => "Οικονομικές",
         "Logical" => "Λογικές",
-        "Date &\nTime" => "Ημερομηνία και\nώρα",
-        "Lookup &\nReference" => "Αναζήτηση και\nαναφορά",
-        "Math &\nTrig" => "Μαθηματικά και\nτριγωνομετρία",
-        "More\nFunctions" => "Περισσότερες\nσυναρτήσεις",
+        "More Functions" => "Περισσότερες συναρτήσεις",
         "Page Layout|Orientation" => "Προσανατολισμός σελίδας",
         "Display theme" => "Θέμα εμφάνισης",
         "System" => "Σύστημα",
diff --git a/crates/ui-egui/src/i18n/es.rs b/crates/ui-egui/src/i18n/es.rs
index a4b4e884a..f3df58b04 100644
--- a/crates/ui-egui/src/i18n/es.rs
+++ b/crates/ui-egui/src/i18n/es.rs
@@ -417,11 +417,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Fecha larga",
         "More Number Formats…" => "Más formatos de número…",
         "Financial" => "Financieras",
+        "Recently Used" => "Usadas recientemente",
         "Logical" => "Lógicas",
-        "Date &\nTime" => "Fecha\ny hora",
-        "Lookup &\nReference" => "Búsqueda y\nreferencia",
-        "Math &\nTrig" => "Matemáticas y\ntrigonométricas",
-        "More\nFunctions" => "Más\nfunciones",
+        "Date & Time" => "Fecha y hora",
+        "Lookup & Reference" => "Búsqueda y referencia",
+        "Math & Trig" => "Matemáticas y trigonométricas",
+        "More Functions" => "Más funciones",
         "Page Layout|Orientation" => "Orientación",
         "Display theme" => "Tema de la interfaz",
         "System" => "Sistema",
diff --git a/crates/ui-egui/src/i18n/fr.rs b/crates/ui-egui/src/i18n/fr.rs
index fdb20f7bf..e44696eb1 100644
--- a/crates/ui-egui/src/i18n/fr.rs
+++ b/crates/ui-egui/src/i18n/fr.rs
@@ -308,11 +308,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Date longue",
         "More Number Formats…" => "Autres formats numériques…",
         "Financial" => "Financières",
+        "Recently Used" => "Récemment utilisées",
         "Logical" => "Logiques",
-        "Date &\nTime" => "Date et\nheure",
-        "Lookup &\nReference" => "Recherche et\nréférence",
-        "Math &\nTrig" => "Maths et\ntrigonométrie",
-        "More\nFunctions" => "Autres\nfonctions",
+        "Date & Time" => "Date et heure",
+        "Lookup & Reference" => "Recherche et référence",
+        "Math & Trig" => "Maths et trigonométrie",
+        "More Functions" => "Autres fonctions",
         "Sheet Options|View" => "Affichage",
         "Print" => "Impression",
         "Print What" => "Quoi imprimer",
diff --git a/crates/ui-egui/src/i18n/it.rs b/crates/ui-egui/src/i18n/it.rs
index 31bc6721c..51d1db6c7 100644
--- a/crates/ui-egui/src/i18n/it.rs
+++ b/crates/ui-egui/src/i18n/it.rs
@@ -291,10 +291,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Altri formati numero…",
         "Financial" => "Finanziarie",
         "Logical" => "Logiche",
-        "Date &\nTime" => "Data e\nora",
-        "Lookup &\nReference" => "Ricerca e\nriferimento",
-        "Math &\nTrig" => "Matematiche e\ntrigonometriche",
-        "More\nFunctions" => "Altre\nfunzioni",
+        "More Functions" => "Altre funzioni",
         "Page Layout|Orientation" => "Orientamento",
         "Display theme" => "Tema di visualizzazione",
         "Animations" => "Animazioni",
diff --git a/crates/ui-egui/src/i18n/ja.rs b/crates/ui-egui/src/i18n/ja.rs
index 1f06755dd..b7cb6c95b 100644
--- a/crates/ui-egui/src/i18n/ja.rs
+++ b/crates/ui-egui/src/i18n/ja.rs
@@ -304,10 +304,8 @@ pub(super) const CORE: &[(&str, &str)] = &[
     ("More Number Formats…", "その他の表示形式…"),
     ("Financial", "財務"),
     ("Logical", "論理"),
-    ("Date &\nTime", "日付/時刻"),
-    ("Lookup &\nReference", "検索/行列"),
-    ("Math &\nTrig", "数学/三角"),
-    ("More\nFunctions", "その他の関数"),
+    ("Recently Used", "最近使用した関数"),
+    ("More Functions", "その他の関数"),
     ("Sheet Options|View", "画面"),
     ("Print", "印刷"),
     ("Print What", "印刷する内容"),
diff --git a/crates/ui-egui/src/i18n/ko.rs b/crates/ui-egui/src/i18n/ko.rs
index c54ed7eee..63159f7db 100644
--- a/crates/ui-egui/src/i18n/ko.rs
+++ b/crates/ui-egui/src/i18n/ko.rs
@@ -295,11 +295,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "자세한 날짜",
         "More Number Formats…" => "숫자 서식 더 보기…",
         "Financial" => "재무",
+        "Recently Used" => "최근 사용 항목",
         "Logical" => "논리",
-        "Date &\nTime" => "날짜 및\n시간",
-        "Lookup &\nReference" => "조회 및\n참조",
-        "Math &\nTrig" => "수학 및\n삼각",
-        "More\nFunctions" => "기타\n함수",
+        "Date & Time" => "날짜 및 시간",
+        "Lookup & Reference" => "조회 및 참조",
+        "Math & Trig" => "수학 및 삼각",
+        "More Functions" => "기타 함수",
         "Page Layout|Orientation" => "용지 방향",
         "Display theme" => "표시 테마",
         "Animations" => "애니메이션",
diff --git a/crates/ui-egui/src/i18n/nl.rs b/crates/ui-egui/src/i18n/nl.rs
index a28459f83..f45fe10a0 100644
--- a/crates/ui-egui/src/i18n/nl.rs
+++ b/crates/ui-egui/src/i18n/nl.rs
@@ -300,10 +300,10 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Meer getalnotaties…",
         "Financial" => "Financieel",
         "Logical" => "Logisch",
-        "Date &\nTime" => "Datum en\ntijd",
-        "Lookup &\nReference" => "Zoeken en\nverwijzen",
-        "Math &\nTrig" => "Wiskunde en\ntrigonometrie",
-        "More\nFunctions" => "Meer\nfuncties",
+        "Date & Time" => "Datum en tijd",
+        "Lookup & Reference" => "Zoeken en verwijzen",
+        "Math & Trig" => "Wiskunde en trigonometrie",
+        "More Functions" => "Meer functies",
         "Sheet Options|View" => "Weergeven",
         "Print" => "Afdrukken",
         "Print What" => "Wat afdrukken",
diff --git a/crates/ui-egui/src/i18n/pl.rs b/crates/ui-egui/src/i18n/pl.rs
index d7741a9c6..3b58b0d20 100644
--- a/crates/ui-egui/src/i18n/pl.rs
+++ b/crates/ui-egui/src/i18n/pl.rs
@@ -287,10 +287,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Więcej formatów liczb…",
         "Financial" => "Finansowe",
         "Logical" => "Logiczne",
-        "Date &\nTime" => "Data i\ngodzina",
-        "Lookup &\nReference" => "Wyszukiwanie\ni odwołania",
-        "Math &\nTrig" => "Matematyczne i\ntrygonometryczne",
-        "More\nFunctions" => "Więcej\nfunkcji",
+        "More Functions" => "Więcej funkcji",
         "Page Layout|Orientation" => "Orientacja",
         "Display theme" => "Motyw wyświetlania",
         "Animations" => "Animacje",
diff --git a/crates/ui-egui/src/i18n/pt.rs b/crates/ui-egui/src/i18n/pt.rs
index c79be64e1..0107235cf 100644
--- a/crates/ui-egui/src/i18n/pt.rs
+++ b/crates/ui-egui/src/i18n/pt.rs
@@ -291,11 +291,9 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Data Por Extenso",
         "More Number Formats…" => "Mais Formatos de Número…",
         "Financial" => "Financeira",
+        "Recently Used" => "Usadas Recentemente",
         "Logical" => "Lógica",
-        "Date &\nTime" => "Data e\nHora",
-        "Lookup &\nReference" => "Pesquisa e\nReferência",
-        "Math &\nTrig" => "Matemática e\nTrigonometria",
-        "More\nFunctions" => "Mais\nFunções",
+        "More Functions" => "Mais Funções",
         "Page Layout|Orientation" => "Orientação",
         "Display theme" => "Tema de exibição",
         "Animations" => "Animações",
diff --git a/crates/ui-egui/src/i18n/ro.rs b/crates/ui-egui/src/i18n/ro.rs
index 058911d87..ade378b9d 100644
--- a/crates/ui-egui/src/i18n/ro.rs
+++ b/crates/ui-egui/src/i18n/ro.rs
@@ -294,10 +294,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Mai multe formate de număr…",
         "Financial" => "Financiare",
         "Logical" => "Logice",
-        "Date &\nTime" => "Dată și\noră",
-        "Lookup &\nReference" => "Căutare și\nreferință",
-        "Math &\nTrig" => "Matematică și\ntrigonometrie",
-        "More\nFunctions" => "Mai multe\nfuncții",
+        "More Functions" => "Mai multe funcții",
         "Page Layout|Orientation" => "Orientare",
         "Display theme" => "Temă de afișare",
         "Animations" => "Animații",
diff --git a/crates/ui-egui/src/i18n/ru.rs b/crates/ui-egui/src/i18n/ru.rs
index b0e894095..f8d46d134 100644
--- a/crates/ui-egui/src/i18n/ru.rs
+++ b/crates/ui-egui/src/i18n/ru.rs
@@ -295,11 +295,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "Длинная дата",
         "More Number Formats…" => "Другие числовые форматы…",
         "Financial" => "Финансовые",
+        "Recently Used" => "Последние",
         "Logical" => "Логические",
-        "Date &\nTime" => "Дата и\nвремя",
-        "Lookup &\nReference" => "Поиск и\nссылки",
-        "Math &\nTrig" => "Математические и\nтригонометрические",
-        "More\nFunctions" => "Другие\nфункции",
+        "Date & Time" => "Дата и время",
+        "Lookup & Reference" => "Поиск и ссылки",
+        "Math & Trig" => "Математические и тригонометрические",
+        "More Functions" => "Другие функции",
         "Page Layout|Orientation" => "Ориентация",
         "Display theme" => "Тема оформления",
         "Animations" => "Анимация",
diff --git a/crates/ui-egui/src/i18n/sr.rs b/crates/ui-egui/src/i18n/sr.rs
index c9ce49e9e..4ff6aa4ce 100644
--- a/crates/ui-egui/src/i18n/sr.rs
+++ b/crates/ui-egui/src/i18n/sr.rs
@@ -299,10 +299,10 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Još formata brojeva…",
         "Financial" => "Finansijsko",
         "Logical" => "Logičko",
-        "Date &\nTime" => "Datum i\nvreme",
-        "Lookup &\nReference" => "Pretraga i\nreference",
-        "Math &\nTrig" => "Matematika i\ntrigonometrija",
-        "More\nFunctions" => "Još\nfunkcija",
+        "Date & Time" => "Datum i vreme",
+        "Lookup & Reference" => "Pretraga i reference",
+        "Math & Trig" => "Matematika i trigonometrija",
+        "More Functions" => "Još funkcija",
         "Sheet Options|View" => "Prikaz",
         "Print" => "Štampaj",
         "Print What" => "Šta štampati",
diff --git a/crates/ui-egui/src/i18n/tr.rs b/crates/ui-egui/src/i18n/tr.rs
index 68cd198bb..f09e64e07 100644
--- a/crates/ui-egui/src/i18n/tr.rs
+++ b/crates/ui-egui/src/i18n/tr.rs
@@ -403,10 +403,10 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Diğer Sayı Biçimleri…",
         "Financial" => "Finansal",
         "Logical" => "Mantıksal",
-        "Date &\nTime" => "Tarih ve\nSaat",
-        "Lookup &\nReference" => "Arama ve\nBaşvuru",
-        "Math &\nTrig" => "Matematik ve\nTrigonometri",
-        "More\nFunctions" => "Diğer\nİşlevler",
+        "Date & Time" => "Tarih ve Saat",
+        "Lookup & Reference" => "Arama ve Başvuru",
+        "Math & Trig" => "Matematik ve Trigonometri",
+        "More Functions" => "Diğer İşlevler",
         "Page Layout|Orientation" => "Sayfa Yönü",
         "Display theme" => "Görüntü teması",
         "System" => "Sistem",
diff --git a/crates/ui-egui/src/i18n/uk.rs b/crates/ui-egui/src/i18n/uk.rs
index 72c1bf474..a17d4da56 100644
--- a/crates/ui-egui/src/i18n/uk.rs
+++ b/crates/ui-egui/src/i18n/uk.rs
@@ -289,10 +289,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Інші числові формати…",
         "Financial" => "Фінансові",
         "Logical" => "Логічні",
-        "Date &\nTime" => "Дата і\nчас",
-        "Lookup &\nReference" => "Пошук і\nпосилання",
-        "Math &\nTrig" => "Математичні і\nтригонометричні",
-        "More\nFunctions" => "Інші\nфункції",
+        "More Functions" => "Інші функції",
         "Page Layout|Orientation" => "Орієнтація",
         "Display theme" => "Тема оформлення",
         "Animations" => "Анімація",
@@ -711,9 +708,9 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Hidden" => "Hidden",
         "Search:" => "Search:",
         "e.g. lookup, average, date" => "e.g. lookup, average, date",
-        "Date & Time" => "Date & Time",
-        "Lookup & Reference" => "Lookup & Reference",
-        "Math & Trig" => "Math & Trig",
+        "Date & Time" => "Дата і час",
+        "Lookup & Reference" => "Пошук і посилання",
+        "Math & Trig" => "Математичні і тригонометричні",
         "Statistical" => "Statistical",
         "Engineering" => "Engineering",
         "Database" => "Database",
diff --git a/crates/ui-egui/src/i18n/vi.rs b/crates/ui-egui/src/i18n/vi.rs
index df76b4a93..9063b7d76 100644
--- a/crates/ui-egui/src/i18n/vi.rs
+++ b/crates/ui-egui/src/i18n/vi.rs
@@ -303,10 +303,10 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "More Number Formats…" => "Định dạng số khác…",
         "Financial" => "Tài chính",
         "Logical" => "Logic",
-        "Date &\nTime" => "Ngày &\nGiờ",
-        "Lookup &\nReference" => "Tra cứu &\nTham chiếu",
-        "Math &\nTrig" => "Toán &\nLượng giác",
-        "More\nFunctions" => "Hàm\nkhác",
+        "Date & Time" => "Ngày & Giờ",
+        "Lookup & Reference" => "Tra cứu & Tham chiếu",
+        "Math & Trig" => "Toán & Lượng giác",
+        "More Functions" => "Hàm khác",
         "Sheet Options|View" => "Xem",
         "Print" => "In",
         "Print What" => "Nội dung in",
diff --git a/crates/ui-egui/src/i18n/zh.rs b/crates/ui-egui/src/i18n/zh.rs
index d6dd0eabd..a95f7684d 100644
--- a/crates/ui-egui/src/i18n/zh.rs
+++ b/crates/ui-egui/src/i18n/zh.rs
@@ -295,11 +295,12 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Long Date" => "长日期",
         "More Number Formats…" => "更多数字格式…",
         "Financial" => "财务",
+        "Recently Used" => "最近使用的函数",
         "Logical" => "逻辑",
-        "Date &\nTime" => "日期和\n时间",
-        "Lookup &\nReference" => "查找和\n引用",
-        "Math &\nTrig" => "数学和\n三角函数",
-        "More\nFunctions" => "更多\n函数",
+        "Date & Time" => "日期和时间",
+        "Lookup & Reference" => "查找和引用",
+        "Math & Trig" => "数学和三角函数",
+        "More Functions" => "更多函数",
         "Page Layout|Orientation" => "纸张方向",
         "Display theme" => "显示主题",
         "Animations" => "动画",
diff --git a/crates/ui-egui/src/icons.rs b/crates/ui-egui/src/icons.rs
index c1f894ea9..e542e627b 100644
--- a/crates/ui-egui/src/icons.rs
+++ b/crates/ui-egui/src/icons.rs
@@ -8,6 +8,27 @@ use egui::{Color32, Painter, Pos2, Rect, Stroke, pos2, vec2};
 
 use crate::theme::{Cat, Tokens};
 
+/// The glyph on a Function Library book ([`Icon::FnBook`]).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum FnGlyph {
+    /// Recently Used: a star.
+    Star,
+    /// Financial: a stack of coins.
+    Coins,
+    /// Logical: a question mark.
+    Question,
+    /// Text: a letter.
+    Letter,
+    /// Date & Time: a clock face.
+    Clock,
+    /// Lookup & Reference: a magnifier.
+    Magnifier,
+    /// Math & Trig: theta.
+    Theta,
+    /// More Functions: three dots.
+    Dots,
+}
+
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum Icon {
     Paste,
@@ -121,6 +142,9 @@ pub enum Icon {
     SheetList,
     Book,
     Folder,
+    /// A book with a coloured spine and a category glyph (Formulas › Function Library). The
+    /// spine and glyph take the accent colour of [`paint_accent`].
+    FnBook(FnGlyph),
     /// Header & Footer: a page with its top / bottom band marked.
     Header,
     Footer,
@@ -170,6 +194,10 @@ impl G<'_> {
         let v: Vec<Pos2> = pts.iter().map(|(x, y)| self.pt(*x, *y)).collect();
         self.p.add(PathShape::line(v, PathStroke::new(w * self.s.clamp(1.0, 2.0), c)));
     }
+    fn closed(&self, pts: &[(f32, f32)], c: Color32, w: f32) {
+        let v: Vec<Pos2> = pts.iter().map(|(x, y)| self.pt(*x, *y)).collect();
+        self.p.add(PathShape::closed_line(v, PathStroke::new(w * self.s.clamp(1.0, 2.0), c)));
+    }
     fn stroke(&self, pts: &[(f32, f32)], c: Color32) {
         self.line(pts, c, 1.15);
     }
@@ -208,17 +236,20 @@ impl G<'_> {
 }
 
 /// The colours an icon draws with besides its main colour: the paper inside documents and cells,
-/// and the category palette for its coloured parts.
+/// the category palette for its coloured parts, and the accent a button asked for.
 #[derive(Clone, Copy, Debug, PartialEq)]
 struct Palette {
     paper: Color32,
     cat: [Color32; 8],
     recording: Color32,
+    /// The accent colour: the coloured part of an icon that has one (a book's spine and glyph),
+    /// otherwise the icon's main colour. `None` draws the icon as it is.
+    accent: Option<Color32>,
 }
 
 impl Palette {
     fn of(t: &Tokens) -> Palette {
-        Palette { paper: t.paper, cat: t.cat, recording: t.recording }
+        Palette { paper: t.paper, cat: t.cat, recording: t.recording, accent: None }
     }
 
     fn cat(&self, c: Cat) -> Color32 {
@@ -242,11 +273,23 @@ pub fn fallback_for_symbol(c: char) -> Option<Icon> {
     }
 }
 
+/// Whether an icon has a part of its own for the accent colour (otherwise the accent recolours
+/// the whole icon).
+fn has_accent_part(icon: Icon) -> bool {
+    matches!(icon, Icon::FnBook(_))
+}
+
 /// Draws `icon` into `rect` (square-ish), in colour `c`, with the current theme's palette.
 pub fn paint(p: &Painter, rect: Rect, icon: Icon, c: Color32) {
     paint_with(p, rect, icon, c, &Palette::of(&Tokens::get(p.ctx())));
 }
 
+/// Draws `icon` like [`paint`], with an accent colour: the icon's coloured part when it has one
+/// (the spine and glyph of [`Icon::FnBook`]), otherwise the whole icon. `None` is [`paint`].
+pub fn paint_accent(p: &Painter, rect: Rect, icon: Icon, c: Color32, accent: Option<Color32>) {
+    paint_with(p, rect, icon, c, &Palette { accent, ..Palette::of(&Tokens::get(p.ctx())) });
+}
+
 /// Draws `icon` on the sheet, which stays white in both themes, so with the light palette.
 pub fn paint_on_sheet(p: &Painter, rect: Rect, icon: Icon, c: Color32) {
     paint_with(p, rect, icon, c, &Palette::of(&Tokens::light()));
@@ -257,6 +300,10 @@ fn paint_with(p: &Painter, rect: Rect, icon: Icon, c: Color32, pal: &Palette) {
     let side = rect.width().min(rect.height());
     let r = Rect::from_center_size(rect.center(), vec2(side, side));
     let g = G { p, r, s: side / 16.0 };
+    let c = match pal.accent {
+        Some(a) if !has_accent_part(icon) => a,
+        _ => c,
+    };
     let light = c.gamma_multiply(0.45);
     let paper = pal.paper;
     let blue = pal.cat(Cat::Blue);
@@ -690,6 +737,46 @@ fn paint_with(p: &Painter, rect: Rect, icon: Icon, c: Color32, pal: &Palette) {
         Icon::Folder => {
             g.poly(&[(1.5, 4.0), (6.0, 4.0), (7.5, 5.5), (14.5, 5.5), (14.5, 13.0), (1.5, 13.0)], yellow);
         }
+        Icon::FnBook(glyph) => {
+            let spine = pal.accent.unwrap_or(c);
+            g.rect(3.0, 1.5, 10.5, 13.0, Some(paper), Some(c));
+            g.rect(3.0, 1.5, 2.5, 13.0, Some(spine), None);
+            let (x, y) = (9.5, 7.8);
+            match glyph {
+                FnGlyph::Star => {
+                    let pts: Vec<(f32, f32)> = (0..10)
+                        .map(|i| {
+                            let a = std::f32::consts::PI * (i as f32 / 5.0 - 0.5);
+                            let rad = if i % 2 == 0 { 3.4 } else { 1.4 };
+                            (x + rad * a.cos(), y + rad * a.sin())
+                        })
+                        .collect();
+                    g.closed(&pts, spine, 1.0);
+                }
+                FnGlyph::Coins => {
+                    for k in 0..3 {
+                        let top = y + 1.6 - k as f32 * 2.3;
+                        g.p.rect_filled(Rect::from_min_max(g.pt(x - 2.8, top), g.pt(x + 2.8, top + 1.7)), 0.9 * g.s, spine);
+                    }
+                }
+                FnGlyph::Question => g.text(x, y, "?", 8.5, spine, (true, false)),
+                FnGlyph::Letter => g.text(x, y, "A", 8.0, spine, (true, false)),
+                FnGlyph::Clock => {
+                    g.circle(x, y, 3.2, None, Some(spine));
+                    g.stroke(&[(x, y - 2.0), (x, y), (x + 1.6, y + 0.9)], spine);
+                }
+                FnGlyph::Magnifier => {
+                    g.circle(x - 0.6, y - 0.6, 2.3, None, Some(spine));
+                    g.line(&[(x + 1.0, y + 1.0), (x + 3.0, y + 3.0)], spine, 1.5);
+                }
+                FnGlyph::Theta => g.text(x, y, "θ", 8.5, spine, (false, false)),
+                FnGlyph::Dots => {
+                    for dx in [-2.4, 0.0, 2.4] {
+                        g.circle(x + dx, y, 0.9, Some(spine), None);
+                    }
+                }
+            }
+        }
         Icon::Header | Icon::Footer => {
             g.rect(3.5, 1.5, 9.0, 13.0, None, Some(c));
             let y = if icon == Icon::Header { 2.5 } else { 11.0 };
diff --git a/crates/ui-egui/src/keytips/keytip_table/generated.rs b/crates/ui-egui/src/keytips/keytip_table/generated.rs
index 2a2509f08..f2d9fc6e8 100644
--- a/crates/ui-egui/src/keytips/keytip_table/generated.rs
+++ b/crates/ui-egui/src/keytips/keytip_table/generated.rs
@@ -242,6 +242,7 @@ pub const SEQUENCES: &[(&str, Entry)] = &[
     ("MO", Entry::Finish(Action::Control("formulas.lookup"))), // Excel: Lookup & Reference Menu; group level: containment(Lookup & Reference)
     ("MP", Entry::Finish(Action::Command("formulas.tracePrecedents"))), // Excel: Trace Precedents
     ("MQ", Entry::Finish(Action::Control("formulas.moreFunctions"))), // Excel: More Functions Menu; group level: containment(More Functions)
+    ("MR", Entry::Finish(Action::Control("formulas.recentlyUsed"))), // Excel: Recently Used Menu; opens the Recently Used menu
     ("MS", Entry::Continue),                                   // Excel: Use in Formula Menu; group level: containment(Use in Formula)
     ("MSP", Entry::Finish(Action::Dialog("pasteName"))),       // Excel: Paste Names
     ("MT", Entry::Finish(Action::Control("formulas.text"))),   // Excel: Text Menu; group level: containment(Text)
diff --git a/crates/ui-egui/src/keytips/keytips.json b/crates/ui-egui/src/keytips/keytips.json
index 5dfe7b2f5..403bc548c 100644
--- a/crates/ui-egui/src/keytips/keytips.json
+++ b/crates/ui-egui/src/keytips/keytips.json
@@ -1658,6 +1658,13 @@
    "note": "group level: containment(More Functions)",
    "target": "formulas.moreFunctions"
   },
+  {
+   "seq": "MR",
+   "kind": "control",
+   "excel": "Recently Used Menu",
+   "note": "opens the Recently Used menu",
+   "target": "formulas.recentlyUsed"
+  },
   {
    "seq": "MS",
    "kind": "continue",
diff --git a/crates/ui-egui/src/lib.rs b/crates/ui-egui/src/lib.rs
index db9ab316f..bdf41f88e 100644
--- a/crates/ui-egui/src/lib.rs
+++ b/crates/ui-egui/src/lib.rs
@@ -32,6 +32,7 @@ mod floating_pictures;
 pub mod fonts;
 pub mod formula_bar;
 mod formula_locale;
+pub mod function_library;
 pub mod grid;
 pub mod i18n;
 pub mod icons;
diff --git a/crates/ui-egui/src/ribbon.rs b/crates/ui-egui/src/ribbon.rs
index 49aba2b0e..b3ce95182 100644
--- a/crates/ui-egui/src/ribbon.rs
+++ b/crates/ui-egui/src/ribbon.rs
@@ -291,3 +291,31 @@ fn contextual_tabs(app: &SheetApp) -> Vec<&'static str> {
     }
     v
 }
+
+#[cfg(test)]
+mod tooltip_tests {
+    /// A ribbon tooltip names its control only; `widgets::tooltip_shortcut` adds the shortcut of
+    /// the platform it runs on. A Command-key glyph written into the text would show on Windows
+    /// and Linux, where the shortcut is a Ctrl or Alt one (AutoSum is Alt+=).
+    #[test]
+    fn tooltips_leave_the_shortcut_to_the_platform_lookup() {
+        let sources = [
+            include_str!("ribbon.rs"),
+            include_str!("ribbon/automate.rs"),
+            include_str!("ribbon/contextual.rs"),
+            include_str!("ribbon/controls.rs"),
+            include_str!("ribbon/data.rs"),
+            include_str!("ribbon/formulas.rs"),
+            include_str!("ribbon/galleries.rs"),
+            include_str!("ribbon/home.rs"),
+            include_str!("ribbon/insert.rs"),
+            include_str!("ribbon/page_layout.rs"),
+            include_str!("ribbon/review.rs"),
+            include_str!("ribbon/shortcuts.rs"),
+            include_str!("ribbon/title_bar.rs"),
+            include_str!("ribbon/view.rs"),
+        ];
+        let mac_only = sources.iter().flat_map(|s| s.lines()).filter(|l| l.contains('\u{2318}')).collect::<Vec<_>>();
+        assert!(mac_only.is_empty(), "Command-key glyph in ribbon text: {mac_only:?}");
+    }
+}
diff --git a/crates/ui-egui/src/ribbon/formulas.rs b/crates/ui-egui/src/ribbon/formulas.rs
index 4f757bdac..464baf4fd 100644
--- a/crates/ui-egui/src/ribbon/formulas.rs
+++ b/crates/ui-egui/src/ribbon/formulas.rs
@@ -1,6 +1,8 @@
 use super::controls::{act, anchor_keytip, control_keytip, invoke, keytip, menu_items, popup_command, sep};
-use super::home::autosum_menu;
-use super::{Icon, SheetApp, Ui, big_button, big_split_button, json, keytip_table, small_button, small_split_button};
+use super::{Cat, Icon, SheetApp, Tokens, Ui, big_button, big_split_button, json, keytip_table, small_button, small_split_button};
+use crate::function_library;
+use crate::icons::FnGlyph;
+use crate::widgets::small_button_accent;
 
 /// How many cells Formulas › Error Checking › Circular References lists.
 const CIRCULAR_MENU_LIMIT: usize = 100;
@@ -19,6 +21,57 @@ fn circular_references(app: &SheetApp) -> Vec<(usize, String, String)> {
         .collect()
 }
 
+/// What a Function Library button's menu lists.
+#[derive(Clone, Copy, Debug)]
+enum LibraryMenu {
+    Recent,
+    Category(&'static str),
+    More,
+}
+
+/// One Function Library category button: its label, its menu, the glyph and colour of its book,
+/// and the control id its keytip sequence targets in `keytips.json`.
+struct LibraryItem {
+    label: &'static str,
+    menu: LibraryMenu,
+    book: (FnGlyph, Cat),
+    keytip: &'static str,
+}
+
+impl LibraryItem {
+    const fn new(label: &'static str, menu: LibraryMenu, book: (FnGlyph, Cat), keytip: &'static str) -> LibraryItem {
+        LibraryItem { label, menu, book, keytip }
+    }
+}
+
+/// The Function Library categories after AutoSum, column by column (three rows each). Every
+/// category has its own colour.
+const LIBRARY: [LibraryItem; 8] = [
+    LibraryItem::new("Recently Used", LibraryMenu::Recent, (FnGlyph::Star, Cat::Amber), "formulas.recentlyUsed"),
+    LibraryItem::new("Financial", LibraryMenu::Category("Financial"), (FnGlyph::Coins, Cat::Green), "formulas.financial"),
+    LibraryItem::new("Logical", LibraryMenu::Category("Logical"), (FnGlyph::Question, Cat::Purple), "formulas.logical"),
+    LibraryItem::new("Text", LibraryMenu::Category("Text"), (FnGlyph::Letter, Cat::Blue), "formulas.text"),
+    LibraryItem::new("Date & Time", LibraryMenu::Category("DateTime"), (FnGlyph::Clock, Cat::Orange), "formulas.dateTime"),
+    LibraryItem::new("Lookup & Reference", LibraryMenu::Category("Lookup"), (FnGlyph::Magnifier, Cat::Teal), "formulas.lookup"),
+    LibraryItem::new("Math & Trig", LibraryMenu::Category("MathTrig"), (FnGlyph::Theta, Cat::Red), "formulas.mathTrig"),
+    LibraryItem::new("More Functions", LibraryMenu::More, (FnGlyph::Dots, Cat::Slate), "formulas.moreFunctions"),
+];
+
+/// One Function Library category button: a book in the category's colour that opens the
+/// category's menu.
+fn library_button(app: &mut SheetApp, ui: &mut Ui, item: &LibraryItem) {
+    let (glyph, cat) = item.book;
+    let accent = Some(Tokens::get(ui.ctx()).cat(cat));
+    let anchor = small_button_accent(ui, Icon::FnBook(glyph), accent, item.label, item.label, true);
+    control_keytip(app, ui, &anchor, item.keytip);
+    let forced = invoke(app, item.keytip);
+    egui::Popup::menu(&anchor).open_memory(popup_command(forced, anchor.clicked())).show(|ui| match item.menu {
+        LibraryMenu::Recent => function_library::recent_menu(app, ui),
+        LibraryMenu::Category(id) => function_library::category_menu(app, ui, id),
+        LibraryMenu::More => function_library::more_menu(app, ui),
+    });
+}
+
 /// The Formulas tab: Insert Function, AutoSum, the function-category menus (names in the formula
 /// language, descriptions in the interface language), defined names, auditing and calculation.
 pub(super) fn formulas(app: &mut SheetApp, ui: &mut Ui) {
@@ -27,42 +80,21 @@ pub(super) fn formulas(app: &mut SheetApp, ui: &mut Ui) {
     if __k.clicked() {
         app.open_dialog("insertFunction", json!({}));
     }
-    let (s, sa) = big_split_button(ui, Icon::Sum, "AutoSum", "AutoSum");
-    control_keytip(app, ui, &sa, "formulas.autoSum");
-    if s.clicked() {
+    // Function Library: AutoSum as a big split button, then the categories in columns of three
+    // labelled small buttons, as Excel lays the group out when the window is not wide enough for
+    // a big button per category.
+    let (sum, sum_arrow) = big_split_button(ui, Icon::Sum, "AutoSum", "AutoSum");
+    control_keytip(app, ui, &sum_arrow, "formulas.autoSum");
+    if sum.clicked() {
         act(app, "formulas.autoSum", json!({}));
     }
-    egui::Popup::menu(&sa).show(|ui| autosum_menu(app, ui));
-    for (label, cat, cid) in [
-        ("Financial", "Financial", "formulas.financial"),
-        ("Logical", "Logical", "formulas.logical"),
-        ("Text", "Text", "formulas.text"),
-        ("Date &\nTime", "DateTime", "formulas.dateTime"),
-        ("Lookup &\nReference", "Lookup", "formulas.lookup"),
-        ("Math &\nTrig", "MathTrig", "formulas.mathTrig"),
-        ("More\nFunctions", "Statistical", "formulas.moreFunctions"),
-    ] {
-        let r = big_button(ui, Icon::Book, label, label, true);
-        control_keytip(app, ui, &r, cid);
-        let forced_c = invoke(app, cid);
-        egui::Popup::menu(&r).open_memory(popup_command(forced_c, r.clicked())).show(|ui| {
-            ui.set_max_height(420.0);
-            egui::ScrollArea::vertical().show(ui, |ui| {
-                for f in gridcraft_engine::cmd::formulas::function_list() {
-                    if f["category"].as_str() == Some(cat)
-                        && let Some(n) = f["name"].as_str()
-                    {
-                        let locale = app.ui.language.formula_locale();
-                        let name =
-                            app.session.active().map(|d| crate::formula_locale::completion_name(n, locale, &d.wb, d.wb.active_sheet())).unwrap_or(n);
-                        let desc = crate::formula_locale::description(n, locale, app.ui.language).unwrap_or_default();
-                        if ui.button(name).on_hover_text(desc).clicked() {
-                            app.run_or_alert("formulas.insertFunction", json!({"name": n}));
-                            ui.close();
-                        }
-                    }
-                }
-            });
+    let forced = invoke(app, "formulas.autoSum");
+    egui::Popup::menu(&sum_arrow).open_memory(popup_command(forced, sum_arrow.clicked())).show(|ui| function_library::auto_sum_menu(app, ui));
+    for column in LIBRARY.chunks(3) {
+        ui.vertical(|ui| {
+            for item in column {
+                library_button(app, ui, item);
+            }
         });
     }
     sep(ui);
@@ -200,3 +232,21 @@ pub(super) fn formulas(app: &mut SheetApp, ui: &mut Ui) {
         }
     });
 }
+
+#[cfg(test)]
+mod function_library_tests {
+    use super::*;
+
+    #[test]
+    fn every_function_library_book_has_its_own_glyph_and_colour() {
+        let books: Vec<(FnGlyph, Cat)> = LIBRARY.iter().map(|i| i.book).collect();
+        assert_eq!(books.len(), 8, "every category is a coloured book");
+        for (i, (glyph, cat)) in books.iter().enumerate() {
+            assert!(books.iter().skip(i + 1).all(|(g, c)| g != glyph && c != cat), "{glyph:?} / {cat:?} is used twice");
+        }
+        assert!(matches!(LIBRARY.first().map(|i| i.menu), Some(LibraryMenu::Recent)));
+        for item in &LIBRARY {
+            assert!(!keytip_table::sequences_for(item.keytip).is_empty(), "{} has a keytip sequence", item.label);
+        }
+    }
+}
diff --git a/crates/ui-egui/src/ribbon/home.rs b/crates/ui-egui/src/ribbon/home.rs
index 72fce56cb..347fec4fb 100644
--- a/crates/ui-egui/src/ribbon/home.rs
+++ b/crates/ui-egui/src/ribbon/home.rs
@@ -469,7 +469,7 @@ pub(super) fn home(app: &mut SheetApp, ui: &mut Ui) {
             if s {
                 act(app, "formulas.autoSum", json!({}));
             }
-            egui::Popup::menu(&sa).show(|ui| autosum_menu(app, ui));
+            egui::Popup::menu(&sa).show(|ui| crate::function_library::auto_sum_menu(app, ui));
         });
         let fill = small_button(ui, Icon::FillDown, "", "Fill", true);
         for sequence in keytip_table::group_extension(
@@ -562,20 +562,6 @@ pub(super) fn home(app: &mut SheetApp, ui: &mut Ui) {
     });
 }
 
-/// The AutoSum menu (Home › Editing and Formulas › Function Library): a function, or the Insert
-/// Function dialog.
-pub(super) fn autosum_menu(app: &mut SheetApp, ui: &mut Ui) {
-    for f in ["SUM", "AVERAGE", "COUNT", "MAX", "MIN"] {
-        if ui.button(f).clicked() {
-            act(app, "formulas.autoSum", json!({"function": f}));
-        }
-    }
-    ui.separator();
-    if ui.button("More Functions…").clicked() {
-        app.open_dialog("insertFunction", json!({}));
-    }
-}
-
 fn font_combo(app: &mut SheetApp, ui: &mut Ui, st: &Style) {
     let name = st.font.name.clone();
     let resp = ui.add_sized([150.0, 24.0], egui::Button::new(egui::RichText::new(&name).font(theme::ui_font(12.5))));
diff --git a/crates/ui-egui/src/widgets.rs b/crates/ui-egui/src/widgets.rs
index 1552db2bb..a2e749921 100644
--- a/crates/ui-egui/src/widgets.rs
+++ b/crates/ui-egui/src/widgets.rs
@@ -183,6 +183,12 @@ fn paint_big_label(ui: &Ui, rect: Rect, lines: &[std::sync::Arc<egui::Galley>],
 
 /// Small ribbon button: 16px icon with optional label to the right.
 pub fn small_button(ui: &mut Ui, icon: Icon, label: &str, tip: &str, dropdown: bool) -> Response {
+    small_button_accent(ui, icon, None, label, tip, dropdown)
+}
+
+/// Small ribbon button whose icon takes an accent colour (see [`icons::paint_accent`]); `None`
+/// draws it like [`small_button`]. A labelled button reports its label to accessibility.
+pub fn small_button_accent(ui: &mut Ui, icon: Icon, accent: Option<Color32>, label: &str, tip: &str, dropdown: bool) -> Response {
     let t = Tokens::get(ui.ctx());
     let font = theme::ui_font(12.5);
     let label = tr(ui, label);
@@ -194,7 +200,7 @@ pub fn small_button(ui: &mut Ui, icon: Icon, label: &str, tip: &str, dropdown: b
     } else if resp.hovered() {
         ui.painter().rect_filled(rect, 4.0, t.hover);
     }
-    icons::paint(ui.painter(), Rect::from_center_size(pos2(rect.left() + 12.0, rect.center().y), vec2(16.0, 16.0)), icon, t.text);
+    icons::paint_accent(ui.painter(), Rect::from_center_size(pos2(rect.left() + 12.0, rect.center().y), vec2(16.0, 16.0)), icon, t.text, accent);
     if !label.is_empty() {
         ui.painter().text(pos2(rect.left() + 24.0, rect.center().y), Align2::LEFT_CENTER, label, font, t.text);
     }
diff --git a/crates/ui-egui/tests/it/chart_resize.rs b/crates/ui-egui/tests/it/chart_resize.rs
index e2fc537ac..d7447dce3 100644
--- a/crates/ui-egui/tests/it/chart_resize.rs
+++ b/crates/ui-egui/tests/it/chart_resize.rs
@@ -152,8 +152,11 @@ fn right_clicking_a_chart_opens_its_menu_not_the_cells() {
     let (mut h, id) = fixture();
     let inside = corner(&h, id) - vec2(100.0, 80.0);
     right_click(&mut h, inside, vec2(0.0, 0.0));
-    // Home › Cells › Delete has the same accessible name; the menu is drawn over the ribbon, last.
-    h.get_all_by_role_and_label(Role::Button, "Delete").last().unwrap().click();
+    // Home › Cells has a Delete button too: take the one in the chart's menu, by the click.
+    h.query_all_by_label("Delete")
+        .min_by(|a, b| a.rect().center().distance(inside).total_cmp(&b.rect().center().distance(inside)))
+        .expect("the chart menu has Delete")
+        .click();
     h.run_steps(3);
     assert!(h.state().session.doc().unwrap().wb.active().unwrap().charts.is_empty());
     assert!(h.state().grid.object_menu.is_none());
diff --git a/crates/ui-egui/tests/it/function_library.rs b/crates/ui-egui/tests/it/function_library.rs
new file mode 100644
index 000000000..917f36642
--- /dev/null
+++ b/crates/ui-egui/tests/it/function_library.rs
@@ -0,0 +1,171 @@
+//! Formulas › Function Library: the labelled buttons, their category menus, the More Functions
+//! cascade, the AutoSum big split button and the Recently Used keytip.
+
+use egui::os::OperatingSystem;
+use egui::{Event, Key, Modifiers, vec2};
+use egui_kittest::kittest::Queryable as _;
+use gridcraft_engine::Session;
+use gridcraft_engine::core::CellRef;
+use gridcraft_ui_egui::SheetApp;
+use serde_json::json;
+
+type Harness = egui_kittest::Harness<'static, SheetApp>;
+
+fn formulas_tab(width: f32) -> Harness {
+    let mut session = Session::new();
+    session.new_workbook();
+    let mut app = crate::common::app(session);
+    app.ui.ribbon_tab = "Formulas".into();
+    crate::common::harness_with(crate::common::builder().with_os(OperatingSystem::Nix).with_size(vec2(width, 760.0)), app, 4)
+}
+
+fn editor_text(h: &Harness) -> Option<String> {
+    h.state().editor.as_ref().map(|e| e.text.clone())
+}
+
+fn input(h: &Harness, cell: &str) -> String {
+    let d = h.state().session.active().unwrap();
+    d.wb.active().unwrap().input_text(CellRef::parse(cell).unwrap())
+}
+
+/// Clicks a button by its name (a tooltip also names an icon-only button, such as the formula
+/// bar's fx, which is not a button to accessibility).
+fn click(h: &mut Harness, label: &str) {
+    h.get_by_role_and_label(egui::accesskit::Role::Button, label).click();
+    h.run_steps(3);
+}
+
+/// Clicks a menu row through accessibility, which reaches rows scrolled out of a long menu.
+fn pick(h: &mut Harness, label: &str) {
+    h.get_by_label(label).click_accesskit();
+    h.run_steps(3);
+}
+
+fn close_menus(h: &mut Harness) {
+    h.key_press(Key::Escape);
+    h.run_steps(2);
+    h.state_mut().editor = None;
+    h.run_steps(2);
+}
+
+#[test]
+fn autosum_is_a_big_split_button_then_the_categories_in_columns_of_three() {
+    let h = formulas_tab(1440.0);
+    let columns: [&[&str]; 3] =
+        [&["Recently Used", "Financial", "Logical"], &["Text", "Date & Time", "Lookup & Reference"], &["Math & Trig", "More Functions"]];
+    let rect = |l: &str| h.get_by_role_and_label(egui::accesskit::Role::Button, l).rect();
+    for column in columns {
+        for pair in column.windows(2) {
+            let (a, b) = (rect(pair[0]), rect(pair[1]));
+            assert!((a.left() - b.left()).abs() < 0.5, "{pair:?} share a left edge");
+            assert!(a.bottom() <= b.top() + 0.5, "{pair:?} stack in order");
+        }
+    }
+    for pair in columns.windows(2) {
+        assert!(rect(pair[0][0]).right() <= rect(pair[1][0]).left(), "columns run left to right");
+    }
+    // Insert Function and AutoSum are big buttons, to the left of the columns.
+    let (insert, sum) = (rect("Insert Function"), rect("AutoSum"));
+    assert!(insert.right() <= sum.left() && sum.right() <= rect("Recently Used").left());
+    assert!(sum.top() <= rect("Recently Used").top() + 0.5, "AutoSum starts at the top of the group");
+    assert!(h.get_by_label("AutoSum options").rect().bottom() > rect("Financial").bottom(), "its arrow part reaches below the second row");
+    // A full column stands where the tab's other columns of three small buttons do (Formula
+    // Auditing's), so it fits the ribbon in any font.
+    let (top, bottom) = (rect("Show Formulas").top(), rect("Evaluate Formula").bottom());
+    for column in &columns[..2] {
+        let (t, b) = (rect(column[0]).top(), rect(column[2]).bottom());
+        assert!((t - top).abs() < 0.5 && (b - bottom).abs() < 0.5, "{column:?} spans {t}..{b}, Formula Auditing {top}..{bottom}");
+    }
+}
+
+#[test]
+fn each_category_menu_lists_its_functions_then_insert_function() {
+    let mut h = formulas_tab(1440.0);
+    // Recently Used lists the functions of formulas entered.
+    h.state_mut().run("cell.set", json!({"cell": "A1", "input": "=SUM(1)+AVERAGE(2)"})).unwrap();
+    h.run_steps(2);
+    for (button, function) in [
+        ("Recently Used", "SUM"),
+        ("Financial", "PMT"),
+        ("Logical", "IF"),
+        ("Text", "CONCAT"),
+        ("Date & Time", "TODAY"),
+        ("Lookup & Reference", "XLOOKUP"),
+        ("Math & Trig", "ROUND"),
+    ] {
+        click(&mut h, button);
+        h.get_by_label("Insert Function…");
+        pick(&mut h, function);
+        assert_eq!(editor_text(&h).as_deref(), Some(format!("={function}(").as_str()), "{button} › {function} starts the formula");
+        close_menus(&mut h);
+    }
+    // The menu's last row opens Insert Function on the menu's category.
+    click(&mut h, "Date & Time");
+    click(&mut h, "Insert Function…");
+    let d = h.state().dialog.as_ref().expect("Insert Function opens");
+    assert_eq!(d.name(), "insertFunction");
+    assert_eq!(d.values.get("category"), Some(&json!("Date & Time")));
+}
+
+#[test]
+fn more_functions_cascades_into_the_remaining_categories() {
+    let mut h = formulas_tab(1440.0);
+    click(&mut h, "More Functions");
+    for c in ["Statistical", "Engineering", "Cube", "Information", "Compatibility", "Web"] {
+        h.get_by_label(c);
+    }
+    click(&mut h, "Engineering");
+    h.get_by_label("Insert Function…");
+    pick(&mut h, "BIN2DEC");
+    assert_eq!(editor_text(&h).as_deref(), Some("=BIN2DEC("));
+    close_menus(&mut h);
+    click(&mut h, "More Functions");
+    click(&mut h, "Statistical");
+    pick(&mut h, "Insert Function…");
+    assert_eq!(h.state().dialog.as_ref().and_then(|d| d.values.get("category")), Some(&json!("Statistical")));
+}
+
+#[test]
+fn autosum_runs_sum_and_its_arrow_opens_the_shared_menu() {
+    let mut h = formulas_tab(1440.0);
+    {
+        let s = &mut h.state_mut().session;
+        s.execute("range.setValues", json!({"range": "A1", "values": [[1, 4], [2, 5], [3, 6]]})).unwrap();
+        s.execute("selection.set", json!({"cell": "A4"})).unwrap();
+    }
+    h.run_steps(2);
+    click(&mut h, "AutoSum");
+    assert_eq!(input(&h, "A4"), "=SUM(A1:A3)");
+    h.state_mut().session.execute("selection.set", json!({"cell": "B4"})).unwrap();
+    click(&mut h, "AutoSum options");
+    for item in ["Sum", "Average", "Max", "Min", "More Functions…"] {
+        h.get_by_label(item);
+    }
+    click(&mut h, "Count Numbers");
+    assert_eq!(input(&h, "B4"), "=COUNT(B1:B3)");
+    click(&mut h, "AutoSum options");
+    click(&mut h, "More Functions…");
+    assert_eq!(h.state().dialog.as_ref().map(|d| d.name().to_string()).as_deref(), Some("insertFunction"));
+}
+
+fn key_event(key: Key, pressed: bool) -> Event {
+    Event::Key { key, physical_key: None, pressed, repeat: false, modifiers: Modifiers::NONE }
+}
+
+#[test]
+fn the_recently_used_keytip_opens_its_menu() {
+    let mut h = formulas_tab(1440.0);
+    // Recently Used lists the functions of formulas entered.
+    h.state_mut().run("cell.set", json!({"cell": "A1", "input": "=SUM(1)+AVERAGE(2)"})).unwrap();
+    h.run_steps(2);
+    h.input_mut().events.extend([key_event(Key::F10, true), key_event(Key::F10, false)]);
+    h.run_steps(2);
+    for k in [Key::M, Key::R] {
+        h.input_mut().events.extend([key_event(k, true), Event::Text(k.name().to_ascii_lowercase()), key_event(k, false)]);
+        h.run_steps(3);
+    }
+    assert_eq!(h.state().keytips.prefix(), None, "MR finishes the sequence");
+    h.get_by_label("Insert Function…");
+    pick(&mut h, "AVERAGE");
+    assert_eq!(editor_text(&h).as_deref(), Some("=AVERAGE("));
+}
diff --git a/crates/ui-egui/tests/it/keytips_generated.rs b/crates/ui-egui/tests/it/keytips_generated.rs
index 810338a48..0b8f0fec4 100644
--- a/crates/ui-egui/tests/it/keytips_generated.rs
+++ b/crates/ui-egui/tests/it/keytips_generated.rs
@@ -1764,6 +1764,14 @@ fn keytip_mq_() {
     assert_eq!(h.state().keytips.prefix(), None);
 }
 
+#[test]
+fn keytip_mr_() {
+    let mut h = harness(blank());
+    sequence(&mut h, "MR", false);
+    assert!(h.state().message.is_none() && h.state().toast.is_none(), "MR must route to its control without an error box");
+    assert_eq!(h.state().keytips.prefix(), None);
+}
+
 #[test]
 fn keytip_ms_() {
     let mut h = harness(blank());
@@ -2754,7 +2762,7 @@ fn keytip_q_() {
 
 #[test]
 fn generated_test_count_matches_the_table() {
-    const EXPECTED: usize = 365;
+    const EXPECTED: usize = 366;
     assert_eq!(gridcraft_ui_egui::keytips::keytip_table::SEQUENCES.len(), EXPECTED);
 }
 
diff --git a/crates/ui-egui/tests/it/main.rs b/crates/ui-egui/tests/it/main.rs
index 302bc9c49..4013f0b4a 100644
--- a/crates/ui-egui/tests/it/main.rs
+++ b/crates/ui-egui/tests/it/main.rs
@@ -47,6 +47,7 @@ mod formula_locale;
 mod formula_point_headers;
 mod formula_popup;
 mod freeze_handles;
+mod function_library;
 mod go_to_dialog;
 mod header_autofit;
 mod header_column_drag;
diff --git a/crates/ui-egui/tests/it/ribbon_layout.rs b/crates/ui-egui/tests/it/ribbon_layout.rs
index faa51b15f..452f8ea33 100644
--- a/crates/ui-egui/tests/it/ribbon_layout.rs
+++ b/crates/ui-egui/tests/it/ribbon_layout.rs
@@ -135,15 +135,15 @@ fn big_split_button_separates_the_default_action_from_the_menu() {
 }
 
 #[test]
-fn formulas_autosum_runs_on_the_icon_and_opens_its_menu_on_the_label() {
+fn formulas_autosum_runs_sum_and_its_arrow_opens_the_menu() {
     let mut h = app_at(1600.0, "Formulas");
     h.get_by_label("AutoSum").click();
     h.run_steps(2);
-    assert!(h.state().session.journal.iter().any(|(id, _)| id == "formulas.autoSum"), "the icon runs AutoSum");
-    assert!(h.query_by_label("AVERAGE").is_none());
+    assert!(h.state().session.journal.iter().any(|(id, _)| id == "formulas.autoSum"), "the button runs AutoSum");
+    assert!(h.query_by_label("Average").is_none());
     h.get_by_label("AutoSum options").click();
     h.run_steps(2);
-    h.get_by_label("AVERAGE").click();
+    h.get_by_label("Average").click();
     h.run_steps(2);
     let last = h.state().session.journal.iter().rev().find(|(id, _)| id == "formulas.autoSum").map(|(_, p)| p.clone());
     assert_eq!(last.and_then(|p| p.get("function").and_then(|f| f.as_str().map(str::to_string))).as_deref(), Some("AVERAGE"));
diff --git a/docs/architecture.md b/docs/architecture.md
index edf1bb679..67bf839f8 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -1,6 +1,6 @@
 # Architecture
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-25 · **Change:** trivial (the hidden names that hold macros; earlier: macro engine on the engine building blocks) · **Target:** Microsoft Excel (Microsoft 365)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-31 · **Change:** minor (Function Library module; accent icons; earlier: the hidden names that hold macros) · **Target:** Microsoft Excel (Microsoft 365)
 
 How GridCraft is built today. Rules for contributors are in [`AGENTS.md`](../AGENTS.md).
 
@@ -59,13 +59,19 @@ drawing its own:
   `icons::paint_on_sheet`) keep their light values. `theme::contrast_tests` holds every
   foreground/background pair to WCAG 2 (4.5:1 for text, 3:1 for glyphs) in both themes; a new
   token pair is added there. Icons (`icons.rs`, drawn in code) take their paper and category
-  colours (`theme::Cat`) from the tokens.
+  colours (`theme::Cat`) from the tokens; `icons::paint_accent` gives an icon an accent colour,
+  drawn on its coloured part when it has one (the spine and glyph of `Icon::FnBook`).
 - **Ribbon widgets**: `widgets.rs` has the buttons every tab is built from (`big_button`,
-  `small_button`, `split_button`, `big_split_button`, `toggle_button`), translated through
-  `i18n` in one place. Split buttons return the main and arrow responses separately, with
-  accessible names (`AutoSum`, `AutoSum options`). The ribbon card scrolls a tab wider than the
-  window, with arrows at its edges; `ribbon::RibbonOverflow` records the groups' size each frame,
+  `small_button`, `small_button_accent`, `split_button`, `big_split_button`, `toggle_button`),
+  translated through `i18n` in one place. Split buttons return the main and arrow responses
+  separately, with accessible names (`AutoSum`, `AutoSum options`); big and small buttons
+  report their label (an icon-only one its tooltip) as their accessible name. The ribbon card
+  scrolls a tab wider than the window, with arrows at its edges; `ribbon::RibbonOverflow` records the groups' size each frame,
   and a test keeps every tab within the card's three rows.
+- **Function Library**: `function_library.rs` holds the function categories (engine id and
+  label, in the Insert Function dialog's order), the function list built once from
+  `cmd::formulas::function_list`, and the menus of Formulas › Function Library, including the
+  AutoSum menu that Home › Editing shares.
 - **Code editor**: `widgets::code_editor(ui, id, &mut text, Lang, max_lines)` (`code_editor.rs`)
   edits code in the monospace font with `Tokens::syntax` colours: Python (keywords, strings
   including triple-quoted ones, numbers, comments, builtins) and LaTeX (commands, scripts,
@@ -159,6 +165,7 @@ rpm, tarball), FreeBSD, and web (WASM; WebGPU or WebGL2). Release workflows in
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-31 | minor | Function Library module (`function_library.rs`); accent icons (`icons::paint_accent`, `widgets::small_button_accent`) |
 | 2026-10-25 | trivial | The hidden names that hold macros are `_gc_macro_<n>_<k>` |
 | 2026-10-24 | minor | Macro engine on the building blocks (`macros/`, `cmd/macros.rs`) |
 | 2026-10-24 | minor | Engine building blocks for multi-command actions: undo groups, recording buffer, document trust, chunked hidden-name storage |
diff --git a/docs/ui-parity.md b/docs/ui-parity.md
index 0e1a98f47..630743d03 100644
--- a/docs/ui-parity.md
+++ b/docs/ui-parity.md
@@ -1,6 +1,6 @@
 # UI parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-30 · **Change:** minor (checkbox cells print as boxes; earlier: Ctrl+arrow and Ctrl+Shift+arrow while pointing a formula reference; earlier: editing a hyperlink loads its existing fields; earlier: AutoSum over a selected row puts its total to the right; ribbon catalog count 276 / 292) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-31 · **Change:** minor (Formulas › Function Library as labelled buttons with category menus; earlier: checkbox cells print as boxes; Ctrl+arrow and Ctrl+Shift+arrow while pointing a formula reference; editing a hyperlink loads its existing fields; AutoSum over a selected row puts its total to the right; ribbon catalog count 276 / 292) · **Target:** Microsoft Excel (Microsoft 365), Excel for Mac 16.113.4
 
 Interaction, controls and feel, against Excel. Part of [target-app-parity.md](target-app-parity.md).
 **UI/UX fidelity: ~55% ready, 50–80 h** (estimated). Ribbon command coverage is measured
@@ -18,6 +18,7 @@ Sources: `crates/ui-egui/src` (ribbon, grid, editor, formula bar, dialogs, panes
 | Title bar, Quick Access Toolbar, AutoSave toggle | yes | yes | done; macOS window controls misaligned (#170), Dock icon size (#169) |
 | Ribbon: tabs, groups, split buttons, galleries, contextual tabs | yes | yes (Table Design, Chart Design, Format, PivotTable, Header & Footer tabs); Fill Color, Font Color and the Format Cells colour pickers end with Recent Colors and More Colors… (#928); large split buttons (Formulas › AutoSum); arrows at the card's edges scroll a tab wider than the window | done; missing contextual tabs for pictures, shapes, sparklines, slicers; groups do not collapse when narrow |
 | Ribbon collapse, simplified ribbon, customize ribbon/QAT | yes | partial | customization missing (File ▸ Options is the one missing File command) |
+| Formulas › Function Library | Insert Function, AutoSum, Recently Used and a menu per function category | yes (10-24): a big Insert Function button and three columns of labelled small buttons, the layout Excel uses when the window is not wide enough for a big button per category; each category's book icon has its own colour; a category menu shows each function's description on hover and ends with Insert Function…, which opens the dialog on that category; More Functions cascades into Statistical, Engineering, Cube, Information, Compatibility and Web; AutoSum is a split button whose menu (Sum, Average, Count Numbers, Max, Min, More Functions…) Home › Editing shares; Recently Used has the MR key tip | the wide layout with a big button per category is not offered; Recently Used lists what `formulas.recentlyUsed` returns |
 | Ribbon: tabs, groups, split buttons, galleries, contextual tabs | yes | yes (Table Design, Chart Design, Format, PivotTable tabs) | done; missing contextual tabs for pictures, shapes, sparklines, header/footer, slicers |
 | Ribbon collapse, simplified ribbon, customize ribbon/QAT | yes | partial | customization missing |
 | Key tips (Alt / F10 then letters) | yes, every ribbon control | **initial** (#43, 10-10): Alt or F10 shows key tips on Home for alignment, Paste Special and AutoFit plus legacy Alt sequences; other tabs and controls not yet (#33, #49) | 3–5 h |
@@ -194,6 +195,7 @@ scrollbar bugs 2–4 · pixel/feel pass against observed Excel 7–12.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-31 | minor | Formulas › Function Library: Insert Function, the AutoSum split button and three columns of labelled small buttons with category colours; category menus end with Insert Function…; More Functions cascades; Home › Editing shares the AutoSum menu; MR key tip for Recently Used |
 | 2026-10-30 | minor | Checkbox cells print and export to PDF as boxes, as on screen: unchecked white with a grey outline, checked green with a white tick (#2972). They printed their value as TRUE or FALSE; other values in a checkbox cell still print as text |
 | 2026-10-29 | minor | Formula pointing from the keyboard: Ctrl+arrow (⌘arrow) moves the pointed cell to the edge of its data and Ctrl+Shift+arrow (⌘⇧arrow) extends the pointed range there, as the same keys move and extend the selection, so typing `=COUNTIF(`, clicking the top of a column and pressing ⌘⇧↓ points at the whole column of data; the keys used to move or extend by one cell. A range reaching the sheet edge is written as whole columns or rows (`A:B`). The editor reads the modifiers of the arrow's own key event, so a keystroke pressed and released within one frame (a control client's `ui.key`, an automation tool) keeps its Shift and Ctrl |
 | 2026-10-29 | minor | Insert Hyperlink opens with an existing link's address, display text and ScreenTip (#2876). An address-only edit preserves the cell's content and formula; Cancel leaves the link unchanged, and Undo restores the edit |