Options: highlight the active cell's row, as a global preference

On a wide table the eye loses its place following a row from the active
cell. File > Options > General gets "Highlight the active cell's row", off
by default: a tint across the whole row of the active cell, over the fills
and under the text, in Normal and Page Layout views. It is a preference for
every sheet and workbook, so nothing goes into the file, the workbook does
not become dirty and there is no undo step.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/app/commands.rs

@@ -191,6 +191,10 @@ impl SheetApp {
                 self.ui.autocomplete = p.get("on").and_then(Json::as_bool).unwrap_or(!self.ui.autocomplete);
                 Ok(json!({"on": self.ui.autocomplete}))
             }
+            "options.highlightActiveRow" => {
+                self.ui.highlight_active_row = p.get("on").and_then(Json::as_bool).unwrap_or(!self.ui.highlight_active_row);
+                Ok(json!({"on": self.ui.highlight_active_row}))
+            }
             "view.interfaceScale" => {
                 // `{"percent": 125}` or `{"percent": "auto"}`; out-of-range values are clamped.
                 let percent = match p.get("percent") {

crates/ui-egui/src/backstage/options.rs

@@ -14,6 +14,10 @@ pub(super) fn options(app: &mut SheetApp, ui: &mut Ui) {
     if ui.checkbox(&mut formula_bar, lang.tr("Show formula bar")).changed() {
         app.run_or_alert("view.formulaBar", json!({"on": formula_bar}));
     }
+    let mut highlight_row = app.ui.highlight_active_row;
+    if ui.checkbox(&mut highlight_row, lang.tr("Highlight the active cell's row")).changed() {
+        app.run_or_alert("options.highlightActiveRow", json!({"on": highlight_row}));
+    }
     ui.add_space(18.0);
     section(ui, lang, "Options|Editing");
     let mut autocomplete = app.ui.autocomplete;

crates/ui-egui/src/control.rs

@@ -269,6 +269,7 @@ pub fn handle(app: &mut SheetApp, ctx: &egui::Context, method: &str, p: &Json) -
                 ("view.theme", "Display Theme", ""),
                 ("view.animations", "Animations", "{on?: bool} (toggles without it) → {on}"),
                 ("options.autoComplete", "Enable AutoComplete for cell values", "{on?: bool} (toggles without it) → {on}"),
+                ("options.highlightActiveRow", "Highlight the active cell's row", "{on?: bool} (toggles without it) → {on}"),
                 ("view.interfaceScale", "Interface Size", "{percent: 75–200 | \"auto\"} (100 = auto; clamped)"),
                 ("ui.dialog", "Open Dialog", ""),
                 ("ui.backstage", "File (Backstage view)", "{page?: home|new|open|info|saveAs|print|export|options|account|close}"),

crates/ui-egui/src/grid.rs

@@ -22,6 +22,8 @@ type PagesCache = ((u64, u64, usize), Vec<(RangeRef, u32)>);
 /// Cached Show Details cells, keyed by (doc uid, revision, sheet, pivot).
 type DetailsCache = ((u64, u64, usize, usize), Option<std::collections::HashSet<(u32, u32)>>);
 
+mod active_row;
+pub use active_row::active_row_band;
 mod cell_paint;
 mod cursor;
 mod editor;

crates/ui-egui/src/grid/active_row.rs

@@ -0,0 +1,28 @@
+//! "Highlight the active cell's row" (File ▸ Options ▸ General): a tint across the whole row of
+//! the active cell, so the eye keeps its place in a wide table.
+
+use super::geo::Geo;
+use super::quadrant::QuadrantPaint;
+use super::{Rect, Sheet, pos2};
+
+/// The tinted band of `row` inside one quadrant (`rows` x `cols`): none when the row is outside
+/// the quadrant or hidden.
+pub fn active_row_band(geo: &Geo, sh: &Sheet, row: u32, rows: (u32, u32), cols: (u32, u32)) -> Option<Rect> {
+    let height = sh.row_height(row) * geo.z;
+    if row < rows.0 || row > rows.1 || height <= 0.0 {
+        return None;
+    }
+    let top = geo.y(sh, row);
+    let right = geo.x(sh, cols.1) + sh.col_width(cols.1) * geo.z;
+    Some(Rect::from_min_max(pos2(geo.x(sh, cols.0), top), pos2(right, top + height)))
+}
+
+/// Paints the band of one quadrant, when the preference is on. With `within`, only the part of it
+/// inside that area (text running past its cell has just cleared it).
+pub(super) fn paint_active_row(q: &QuadrantPaint<'_>, within: Option<Rect>) {
+    let Some(band) = q.active_row.and_then(|row| active_row_band(q.geo, q.sheet, row, q.rows, q.cols)) else { return };
+    let part = within.map_or(band, |area| band.intersect(area));
+    if part.is_positive() {
+        q.painter.rect_filled(part, 0.0, q.tokens.active_row);
+    }
+}

crates/ui-egui/src/grid/quadrant.rs

@@ -1,3 +1,4 @@
+use super::active_row::paint_active_row;
 use super::cell_paint::{
     Look, MergedArea, cell_text_y, center_across_end, col32, display_text, look, merged_edges, paint_border, paint_cf_icon, painted_halign,
     rotated_text_pos, shrink_font, wrapped_cell_text_y,
@@ -102,6 +103,8 @@ pub(crate) struct QuadrantPaint<'a> {
     pub(crate) cols: (u32, u32),
     pub(crate) cf: &'a mut CfCache,
     pub(crate) tokens: &'a Tokens,
+    /// The row to tint, when "Highlight the active cell's row" is on.
+    pub(crate) active_row: Option<u32>,
 }
 
 /// Paint a worksheet quadrant, including backgrounds, borders, and text.
@@ -118,6 +121,8 @@ pub(crate) fn paint_quadrant(mut quadrant: QuadrantPaint<'_>) {
     let cells = visible_cells(&quadrant);
     let looks = paint_backgrounds(&mut quadrant, &cells, &merges);
     let outside = outside_text_cells(&mut quadrant, &merges);
+    // Over the fills and under the text and borders.
+    paint_active_row(&quadrant, None);
     paint_cells(&mut quadrant, &looks, &outside, &merges);
     paint_borders(&mut quadrant, &looks, &merges);
     paint_sparklines(&quadrant, range);
@@ -478,9 +483,11 @@ fn paint_cell(q: &QuadrantPaint<'_>, painted: &(CellRef, Rect, Look, Option<CfLo
             let extra_r = Rect::from_min_max(pos2(rect.right() - 1.0, inner.top()), inner.max);
             if extra_l.width() > 0.0 {
                 p.rect_filled(extra_l, 0.0, t.grid_bg);
+                paint_active_row(q, Some(extra_l));
             }
             if extra_r.width() > 0.0 {
                 p.rect_filled(extra_r, 0.0, t.grid_bg);
+                paint_active_row(q, Some(extra_r));
             }
         }
     }

crates/ui-egui/src/grid/show.rs

@@ -404,7 +404,19 @@ fn paint_panes(input: PanesInput<'_>, cf: &mut CfCache) -> Vec<PaneQuad> {
             continue;
         }
         let p = painter.with_clip_rect(*clip);
-        paint_quadrant(QuadrantPaint { painter: &p, geo, workbook: wb, sheet_index: si, sheet: sh, rows: *rows, cols: *cols, cf, tokens: t });
+        let active_row = app.ui.highlight_active_row.then_some(sel.active.row);
+        paint_quadrant(QuadrantPaint {
+            painter: &p,
+            geo,
+            workbook: wb,
+            sheet_index: si,
+            sheet: sh,
+            rows: *rows,
+            cols: *cols,
+            cf,
+            tokens: t,
+            active_row,
+        });
         paint_selection(SelectionPaintInput { painter: &p, geo, sheet: sh, selection: sel, outline, tokens: t, app, rows: *rows, cols: *cols });
     }
     // Freeze lines.

crates/ui-egui/src/i18n/it.rs

@@ -410,6 +410,7 @@ pub(super) fn translate(text: &str) -> Option<&'static str> {
         "Options|Save" => "Salvataggio",
         "Options|Editing" => "Modifica",
         "Show formula bar" => "Mostra barra della formula",
+        "Highlight the active cell's row" => "Evidenzia la riga della cella attiva",
         "Enable AutoComplete for cell values" => "Abilita Completamento automatico per i valori delle celle",
         "Save .xlsx workbooks automatically after every change" => "Salva automaticamente le cartelle di lavoro .xlsx dopo ogni modifica",
         "Workbook calculation" => "Calcolo della cartella di lavoro",

crates/ui-egui/src/lib.rs

@@ -94,6 +94,9 @@ pub struct UiState {
     /// Enable AutoComplete for cell values (File ▸ Options ▸ Editing): typed text is completed
     /// from the one matching entry in the same column.
     pub autocomplete: bool,
+    /// Tint the active cell's whole row (File ▸ Options ▸ General), on every sheet and workbook, so
+    /// the eye keeps its place across a wide table. A preference: nothing goes into the file.
+    pub highlight_active_row: bool,
     /// AutoSave (the title-bar switch): save saved-to-file .xlsx workbooks shortly after every
     /// change. A preference like the rest of this struct — it stays on across restarts (#1901).
     pub autosave: bool,
@@ -140,6 +143,7 @@ impl Default for UiState {
             status_bar: true,
             animations: true,
             autocomplete: true,
+            highlight_active_row: false,
             autosave: false,
             recent: vec![],
             keytip_invoke: None,

crates/ui-egui/src/paper_view.rs

@@ -162,7 +162,19 @@ pub(crate) fn paint_pages(input: PagePaintInput<'_>, cf: &mut CfCache) -> Vec<gr
         }
         painted += 1;
         let pc = p.with_clip_rect(clip);
-        grid::paint_quadrant(grid::QuadrantPaint { painter: &pc, geo, workbook: wb, sheet_index: si, sheet: sh, rows, cols, cf, tokens: t });
+        let active_row = app.ui.highlight_active_row.then_some(sel.active.row);
+        grid::paint_quadrant(grid::QuadrantPaint {
+            painter: &pc,
+            geo,
+            workbook: wb,
+            sheet_index: si,
+            sheet: sh,
+            rows,
+            cols,
+            cf,
+            tokens: t,
+            active_row,
+        });
         if !pg.is_data_page(i, j) {
             // "Click to add data" pages: faded until something is typed there.
             pc.rect_filled(clip, 0.0, t.grid_bg.gamma_multiply(0.75));

crates/ui-egui/src/theme.rs

@@ -63,6 +63,8 @@ pub struct Tokens {
     pub header_sel_text: Color32,
     pub header_all_bg: Color32,
     pub sel_fill: Color32,
+    /// The tint over the active cell's row (File ▸ Options ▸ General).
+    pub active_row: Color32,
     pub sel_border: Color32,
     pub input_bg: Color32,
     pub input_border: Color32,
@@ -217,6 +219,7 @@ impl Tokens {
             header_sel_text: pick(dark, Color32::from_rgb(0x0B, 0x5E, 0x31), Color32::from_rgb(0x6F, 0xD3, 0x9A)),
             header_all_bg: pick(dark, Color32::from_rgb(0xC8, 0xE6, 0xD3), Color32::from_rgb(0x2E, 0x55, 0x3E)),
             sel_fill: pick(dark, Color32::from_rgba_unmultiplied(0x10, 0x7C, 0x41, 0x1C), Color32::from_rgba_unmultiplied(0x10, 0x7C, 0x41, 0x24)),
+            active_row: pick(dark, Color32::from_rgba_unmultiplied(0x10, 0x7C, 0x41, 0x2C), Color32::from_rgba_unmultiplied(0x6F, 0xD3, 0x9A, 0x30)),
             sel_border: Color32::from_rgb(0x10, 0x7C, 0x41),
             input_bg: pick(dark, Color32::WHITE, Color32::from_rgb(0x1F, 0x1F, 0x1F)),
             input_border: pick(dark, Color32::from_rgb(0xD1, 0xD1, 0xD1), Color32::from_rgb(0x50, 0x50, 0x50)),

crates/ui-egui/tests/it/active_row_highlight.rs

@@ -0,0 +1,124 @@
+//! "Highlight the active cell's row": a global preference, off by default, that tints the whole
+//! row of the active cell and leaves the workbook alone.
+
+use egui::{Shape, vec2};
+use gridcraft_engine::Session;
+use gridcraft_engine::core::CellRef;
+use gridcraft_ui_egui::theme::Tokens;
+use gridcraft_ui_egui::{SheetApp, UiState, grid::Geo, grid::active_row_band};
+use serde_json::json;
+
+fn harness(session: Session) -> egui_kittest::Harness<'static, SheetApp> {
+    let mut h = crate::common::builder().with_size(vec2(1200.0, 800.0)).build_ui_state(
+        |ui, app: &mut SheetApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        crate::common::app(session),
+    );
+    h.run_steps(4);
+    h
+}
+
+fn book(active: &str) -> Session {
+    let mut session = Session::new();
+    session.new_workbook();
+    session.execute("selection.set", json!({"range": active})).unwrap();
+    session
+}
+
+/// The rectangles painted with the highlight's own colour.
+fn tinted(h: &egui_kittest::Harness<'_, SheetApp>) -> Vec<egui::Rect> {
+    let tint = Tokens::get(&h.ctx).active_row;
+    h.output()
+        .shapes
+        .iter()
+        .filter_map(|clipped| match &clipped.shape {
+            Shape::Rect(r) if r.fill == tint => Some(r.rect),
+            _ => None,
+        })
+        .collect()
+}
+
+#[test]
+fn it_is_off_by_default_and_paints_nothing() {
+    assert!(!UiState::default().highlight_active_row);
+    let h = harness(book("C5"));
+    assert!(tinted(&h).is_empty());
+}
+
+#[test]
+fn turned_on_it_tints_the_active_row_across_the_columns() {
+    let mut h = harness(book("C5"));
+    assert_eq!(h.state_mut().run("options.highlightActiveRow", json!({"on": true})), Ok(json!({"on": true})));
+    h.run_steps(2);
+    let bands = tinted(&h);
+    assert_eq!(bands.len(), 1, "{bands:?}");
+    let app = h.state();
+    let sheet = app.session.active().unwrap().wb.active().unwrap();
+    let geo = Geo::new(sheet, app.grid.rect.unwrap(), app.view().scroll);
+    let cell = geo.cell_rect(sheet, CellRef::parse("C5").unwrap());
+    assert_eq!((bands[0].top(), bands[0].bottom()), (cell.top(), cell.bottom()));
+    assert!(bands[0].left() <= geo.cells.left() + 1.0, "starts at the first column: {:?}", bands[0]);
+    assert!(bands[0].right() >= geo.cells.right() - 1.0, "reaches the last visible column: {:?}", bands[0]);
+}
+
+#[test]
+fn the_band_follows_the_active_cell_and_only_the_row() {
+    let mut h = harness(book("C5"));
+    h.state_mut().run("options.highlightActiveRow", json!({"on": true})).unwrap();
+    h.state_mut().session.execute("selection.set", json!({"range": "E9"})).unwrap();
+    h.run_steps(2);
+    let bands = tinted(&h);
+    assert_eq!(bands.len(), 1, "a row, and no column band: {bands:?}");
+    let app = h.state();
+    let sheet = app.session.active().unwrap().wb.active().unwrap();
+    let geo = Geo::new(sheet, app.grid.rect.unwrap(), app.view().scroll);
+    assert_eq!(bands[0].top(), geo.cell_rect(sheet, CellRef::parse("E9").unwrap()).top());
+}
+
+#[test]
+fn it_applies_to_every_sheet_and_workbook() {
+    let mut h = harness(book("C5"));
+    h.state_mut().run("options.highlightActiveRow", json!({"on": true})).unwrap();
+    h.state_mut().session.execute("home.insertSheet", json!({"name": "Other"})).unwrap();
+    h.run_steps(2);
+    assert_eq!(tinted(&h).len(), 1, "another sheet");
+    h.state_mut().session.new_workbook();
+    h.run_steps(2);
+    assert_eq!(tinted(&h).len(), 1, "another workbook");
+}
+
+#[test]
+fn turning_it_off_clears_the_band_and_the_toggle_leaves_the_workbook_alone() {
+    let mut h = harness(book("C5"));
+    let dirty = h.state().session.active().unwrap().is_dirty();
+    assert_eq!(h.state_mut().run("options.highlightActiveRow", json!({})), Ok(json!({"on": true})), "no parameters: it toggles");
+    h.run_steps(2);
+    assert_eq!(h.state().session.active().unwrap().is_dirty(), dirty);
+    assert_eq!(h.state_mut().run("options.highlightActiveRow", json!({})), Ok(json!({"on": false})));
+    h.run_steps(2);
+    assert!(tinted(&h).is_empty());
+    assert_eq!(h.state().session.active().unwrap().is_dirty(), dirty);
+}
+
+#[test]
+fn the_preference_survives_a_restart_and_older_settings_read_as_off() {
+    let state = UiState { highlight_active_row: true, ..UiState::default() };
+    let saved = serde_json::to_string(&state).unwrap();
+    assert!(serde_json::from_str::<UiState>(&saved).unwrap().highlight_active_row);
+    assert!(!serde_json::from_str::<UiState>("{}").unwrap().highlight_active_row);
+}
+
+#[test]
+fn a_hidden_row_or_a_row_outside_the_quadrant_has_no_band() {
+    let mut session = book("A1");
+    session.execute("home.rowHeight", json!({"rows": "5:5", "height": 0})).unwrap();
+    let h = harness(session);
+    let app = h.state();
+    let sheet = app.session.active().unwrap().wb.active().unwrap();
+    let geo = Geo::new(sheet, app.grid.rect.unwrap(), app.view().scroll);
+    assert_eq!(active_row_band(&geo, sheet, 4, (0, 20), (0, 5)), None, "hidden");
+    assert_eq!(active_row_band(&geo, sheet, 30, (0, 20), (0, 5)), None, "outside");
+    assert!(active_row_band(&geo, sheet, 6, (0, 20), (0, 5)).is_some());
+}

crates/ui-egui/tests/it/main.rs

@@ -7,6 +7,7 @@
 mod common;
 
 mod accounting_fill;
+mod active_row_highlight;
 mod advanced_filter;
 mod argument_names;
 mod autosave_persist;

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-02 · **Change:** minor (RefEdit reference boxes in dialogs: Goal Seek, Solver and Data Analysis use them, the arrow keys select while a dialog is collapsed and F4 cycles a reference's anchors; earlier: Python cells: Python mode in the formula bar; earlier: Insert › Equation and the equation editor; earlier: every floating object selects, resizes from eight handles and deletes with the keyboard; earlier: Formulas › Error Checking › Trace Error; trace arrows stay through a zoom (#3097); earlier: Page Setup sets the page order, Down, then over or Over, then down, which printing, the print preview, Page Break Preview and Page Layout view follow; earlier: Formulas › Function Library as labelled buttons with category menus; Recently Used and the Insert Function categories; Esc leaves a File-page text field before closing the view; 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
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-03 · **Change:** minor (Highlight the active cell's row, a global preference in File › Options › General; earlier: RefEdit reference boxes in dialogs: Goal Seek, Solver and Data Analysis use them, the arrow keys select while a dialog is collapsed and F4 cycles a reference's anchors; earlier: Python cells: Python mode in the formula bar; earlier: Insert › Equation and the equation editor; earlier: every floating object selects, resizes from eight handles and deletes with the keyboard; earlier: Formulas › Error Checking › Trace Error; trace arrows stay through a zoom (#3097); earlier: Page Setup sets the page order, Down, then over or Over, then down, which printing, the print preview, Page Break Preview and Page Layout view follow; earlier: Formulas › Function Library as labelled buttons with category menus; Recently Used and the Insert Function categories; Esc leaves a File-page text field before closing the view; 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
@@ -54,6 +54,7 @@ this logic, with one undo step.
 | Click/drag/Shift/Ctrl selection, multi-area selection | rectangular drag works in one direction only in some cases (#28) |
 | Cursor while dragging cells, headers, freeze handles and objects | stable for the active drag (#936); Draw tools keep their crosshair; header arrows and a custom cell cursor remain unimplemented |
 | Selection outline glides to a new selection (Excel: "Provide feedback with animation") | done (10-11): 0.12 s, decelerating, with the fill and fill handle; View ▸ Animations (`view.animations`) turns it off. The timing is an estimate, not yet measured against Excel; the system's reduced-motion setting isn't followed yet |
+| Highlight the active cell's row (no Excel equivalent; Focus Cell tints the row and the column) | done (11-03): File › Options › General, off by default; a preference for every sheet and workbook, nothing saved in the file. Tints over the fills and under the text, in Normal and Page Layout views (`options.highlightActiveRow`) |
 | Fill handle: drag to fill series, double-click to fill down, right-drag menu | fill done (Ctrl+drag swaps copy and series; month patterns use the workbook's 1900 or 1904 date system); right-drag menu partial: Copy Cells, Fill Series, Fill Formatting Only, Fill Without Formatting, and from a date Fill Days, Fill Weekdays, Fill Months and Fill Years, then Series…; a left-drag leaves an Auto Fill Options button with the same fill choices (gone once the workbook changes or the selection moves); Linear/Growth Trend and Flash Fill missing |
 | Drag-move and drag-copy cells (border drag, Ctrl/Option, Shift to insert) | done (M3) |
 | In-cell editing, Enter/Tab movement, Alt/Option+Enter line breaks | done |
@@ -237,6 +238,7 @@ scrollbar bugs 2–4 · pixel/feel pass against observed Excel 7–12.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-03 | minor | Highlight the active cell's row: a global preference that tints the whole row, off by default |
 | 2026-11-02 | minor | RefEdit reference boxes in dialogs: pick a range on the grid, collapse the dialog while selecting; Goal Seek, Solver (with the Model Range of Load/Save) and Data Analysis use them; while collapsed the arrow keys move the selection and Shift+arrow extends it, F4 cycles a reference's anchors, a click elsewhere keeps the box picking, a dialog opened over a picking one puts the selection back, OK stays on the sheet its command showed, and scripted cancel and confirm end a pick like the buttons; the dialog's sheet is followed through the recorded undo steps, so a sheet deleted and recreated under its name is not taken for it and an undo of the deletion brings it back; a box the dialog stops showing is no longer picked into |
 | 2026-11-02 | minor | Python mode edits a cell's code in the formula bar's code editor (Ctrl+Alt+Shift+P, `=PY` then Tab, editing a Python cell), with the PY badge beside fx; its keys apply in input order, also several in one frame, and Ctrl+Enter commits through `python.set` (empty code clears the cell), keeping the code and showing the command's message when the code is refused |
 | 2026-11-02 | minor | Insert › Symbols: Equation split button (access keys N E), a gallery of examples, and an equation editor with quick-insert buttons, the error underlined at its position and a live preview; double-clicking an equation edits it |