Merge PR #3226

crates/engine/src/cmd/edit.rs

@@ -36,7 +36,7 @@ use go_to::go_to_special;
 use go_to::{GO_TO_MAX_AREAS, GO_TO_RECENT, reference_parts};
 use paste_special::paste_special;
 pub(crate) use paste_special::{rewrite_all_formulas, rewrite_cell_links, rewrite_python_refs};
-use selection::{select_all, select_col, select_region, select_row, selection_move, selection_next, selection_set};
+use selection::{select_all, select_col, select_region, select_row, selection_move, selection_next, selection_next_corner, selection_set};
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
@@ -62,6 +62,15 @@ pub fn specs() -> Vec<CommandSpec> {
         cmd!(noundo "selection.set", "Select", [], None, "{range: \"A1:B2,D4\" | cell, active?: \"A1\", sheet?}", has_doc, selection_set),
         cmd!(noundo "selection.move", "Move Selection", [], None, "{dr, dc, extend?: bool, jump?: bool (Ctrl+arrow), page?: bool}", has_doc, selection_move),
         cmd!(noundo "selection.next", "Next Cell in Selection", [], None, "{forward?: true, byRow?: false} (Enter/Tab inside a selection)", has_doc, selection_next),
+        cmd!(
+            noundo "selection.nextCorner",
+            "Next Corner of Selection",
+            [],
+            Some("Ctrl+."),
+            "{} (the active cell moves clockwise to the next corner of the selected area, which stays selected)",
+            has_doc,
+            selection_next_corner
+        ),
         cmd!(noundo "edit.selectAll", "Select All", ["Edit"], Some("Cmd+A"), "{} (current region first, then the whole sheet)", has_doc, select_all),
         cmd!(noundo "selection.currentRegion", "Select Current Region", [], Some("Ctrl+Shift+8"), "{}", has_doc, select_region),
         cmd!(noundo "selection.row", "Select Entire Row", [], Some("Shift+Space"), "{}", has_doc, select_row),

crates/engine/src/cmd/edit/selection.rs

@@ -137,6 +137,23 @@ pub(super) fn selection_next(s: &mut Session, p: &Json) -> Result<Json> {
     Ok(json!({"active": d.selection.active.a1()}))
 }
 
+pub(super) fn selection_next_corner(s: &mut Session, _: &Json) -> Result<Json> {
+    let d = s.doc_mut()?;
+    let Some(sheet) = d.wb.active() else { return Err(EngineError::NoDocument) };
+    // A corner in a merged cell lands on its top-left cell. One in a hidden row or column, one
+    // the sheet's protection doesn't let you select, and a merged cell that starts outside the
+    // selected area are skipped.
+    let area = d.selection.current();
+    let stop = |c: CellRef| {
+        Some(sheet.merge_at(c).map_or(c, |m| m.start))
+            .filter(|c| area.contains(*c) && !sheet.is_row_hidden(c.row) && !sheet.is_col_hidden(c.col) && cell_selectable(&d.wb, sheet, *c))
+    };
+    let mut next = d.selection.clone();
+    next.next_corner_by(stop);
+    d.selection = next;
+    Ok(json!({"active": d.selection.active.a1(), "selection": d.selection.a1()}))
+}
+
 pub(super) fn select_all(s: &mut Session, _: &Json) -> Result<Json> {
     let d = s.doc_mut()?;
     let Some(sheet) = d.wb.active() else { return Err(EngineError::NoDocument) };

crates/engine/src/cmd/edit/tests.rs

@@ -439,3 +439,75 @@ fn replace_case_insensitive_keeps_text_when_folding_moves_boundaries() {
     let sh = s.doc().unwrap().wb.active().unwrap();
     assert_eq!(sh.value(CellRef::new(0, 0)), Value::text(text));
 }
+
+#[test]
+fn next_corner_of_selection_goes_clockwise_and_anchors_there() {
+    // #1442, as Excel does it: B2 → D2 → D4 → B4 → B2, the area stays selected, and Shift+arrows
+    // then move the corner opposite the new active cell.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("selection.set", json!({"range": "B2:D4", "active": "B2"})).unwrap();
+    let mut seen = Vec::new();
+    for _ in 0..4 {
+        let r = s.execute("selection.nextCorner", json!({})).unwrap();
+        assert_eq!(r["selection"], "B2:D4");
+        seen.push(r["active"].as_str().unwrap().to_string());
+    }
+    assert_eq!(seen, ["D2", "D4", "B4", "B2"]);
+    s.execute("selection.nextCorner", json!({})).unwrap();
+    s.execute("selection.nextCorner", json!({})).unwrap();
+    s.execute("selection.move", json!({"dr": 0, "dc": 1, "extend": true})).unwrap();
+    assert_eq!(s.doc().unwrap().selection.current().a1(), "C2:D4");
+    // One row goes end to end; a single cell stays.
+    s.execute("selection.set", json!({"range": "B2:D2", "active": "B2"})).unwrap();
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "D2");
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "B2");
+    s.execute("selection.set", json!({"range": "C5"})).unwrap();
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "C5");
+}
+
+#[test]
+fn next_corner_skips_corners_the_sheet_protection_does_not_let_you_select() {
+    // With locked cells unselectable, Ctrl+. goes on to the next corner it may select.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("home.lockCell", json!({"range": "B2:C3", "on": false})).unwrap();
+    s.execute("selection.set", json!({"range": "B2:D3", "active": "B2"})).unwrap();
+    s.execute("review.protectSheet", json!({"selectLockedCells": false})).unwrap();
+    let r = s.execute("selection.nextCorner", json!({})).unwrap();
+    assert_eq!((r["active"].as_str(), r["selection"].as_str()), (Some("B3"), Some("B2:D3")), "D2 and D3 are locked");
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "B2");
+}
+
+#[test]
+fn next_corner_stops_once_on_a_merged_corner_at_its_top_left_cell() {
+    // A corner inside a merged cell is that merged cell, whose active cell is its top-left one.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("home.mergeCells", json!({"range": "C2:D2"})).unwrap();
+    s.execute("selection.set", json!({"range": "B2:D3", "active": "B2"})).unwrap();
+    let seen: Vec<String> = (0..4).map(|_| s.execute("selection.nextCorner", json!({})).unwrap()["active"].as_str().unwrap().to_string()).collect();
+    assert_eq!(seen, ["C2", "D3", "B3", "B2"]);
+    // A selection that is one merged cell has no other corner.
+    s.execute("selection.set", json!({"range": "C2:D2", "active": "C2"})).unwrap();
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "C2");
+}
+
+#[test]
+fn next_corner_skips_hidden_corners_and_stays_inside_the_selected_area() {
+    // A corner in a hidden column is passed over, as keyboard moves pass over hidden cells.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("home.hideColumns", json!({"cols": "D:D"})).unwrap();
+    s.execute("selection.set", json!({"range": "B2:D3", "active": "B2"})).unwrap();
+    assert_eq!(s.execute("selection.nextCorner", json!({})).unwrap()["active"], "B3");
+    // Column C selected with B1:C1 merged: its top corner's merged cell starts in column B,
+    // outside the selection, so the active cell doesn't go there.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("home.mergeCells", json!({"range": "B1:C1"})).unwrap();
+    s.execute("selection.set", json!({"cell": "C5"})).unwrap();
+    s.execute("selection.column", json!({})).unwrap();
+    let r = s.execute("selection.nextCorner", json!({})).unwrap();
+    assert_eq!((r["active"].as_str(), r["selection"].as_str()), (Some("C1048576"), Some("C:C")));
+}

crates/engine/src/selection.rs

@@ -128,6 +128,32 @@ impl Selection {
     }
 }
 
+impl Selection {
+    /// Ctrl+. (Next Corner of Selection): the active cell moves clockwise to the next corner of
+    /// the current area (top-left, top-right, bottom-right, bottom-left) and becomes the anchor,
+    /// so Shift+arrows then move the opposite corner. The area stays selected. From a cell that
+    /// isn't a corner the next corner is the top-left one; a single cell stays where it is.
+    pub fn next_corner(&mut self) {
+        self.next_corner_by(Some);
+    }
+
+    /// [`Selection::next_corner`] where `stop` says where each corner takes the active cell: the
+    /// top-left cell of a merged cell the corner is in, or `None` for a corner that can't be
+    /// selected (it is skipped). Corners that end up on the active cell are one stop with it.
+    pub fn next_corner_by(&mut self, stop: impl Fn(CellRef) -> Option<CellRef>) {
+        let r = self.current();
+        let corners = [r.start, CellRef::new(r.start.row, r.end.col), r.end, CellRef::new(r.end.row, r.start.col)];
+        let next = match corners.iter().rposition(|c| stop(*c) == Some(self.active)) {
+            Some(i) => (1..=4).filter_map(|k| corners.get((i + k) % 4)).filter_map(|c| stop(*c)).find(|c| *c != self.active),
+            None => corners.iter().find_map(|c| stop(*c)),
+        };
+        if let Some(next) = next {
+            self.active = next;
+            self.anchor = next;
+        }
+    }
+}
+
 /// Ctrl+arrow: jump to the edge of the current data region (Excel's End mode).
 pub fn jump(sheet: &Sheet, from: CellRef, dr: i64, dc: i64) -> CellRef {
     if dr == 0 && dc == 0 {

crates/ui-egui/src/keymap.rs

@@ -115,6 +115,8 @@ fn lookup_number_formats(ctx: LookupContext) -> Option<Shortcut> {
         Num7 if ctrl && s => borders("outside"),
         Minus if ctrl && s => borders("none"),
         Num8 if ctrl && s => run("selection.currentRegion"),
+        // Ctrl+. (Control on a Mac too): Next Corner of Selection.
+        Period if ctrl && !s => run("selection.nextCorner"),
         Semicolon if ctrl && s => Shortcut::Time,
         Quote if ctrl && s => Shortcut::ValueAbove,
         Quote if ctrl => Shortcut::FormulaAbove,

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

@@ -100,6 +100,11 @@ fn windows_and_mac_variants() {
     assert_eq!(lookup(Key::ArrowLeft, Some(Key::Num4), alt_shift, false), run("data.ungroup"));
     assert_eq!(lookup(Key::PageDown, Some(Key::Num3), Modifiers::ALT, false), Some(Shortcut::ScreenRight));
     assert_eq!(lookup(Key::PageDown, Some(Key::Num3), CTRL_SHIFT, false), None);
+    // Ctrl+. is Next Corner of Selection, with Control on a Mac too (#1442); Cmd+Shift+. stays
+    // Increase Font Size.
+    assert_eq!(lookup(Key::Period, Some(Key::Period), cmd, false), run("selection.nextCorner"));
+    assert_eq!(lookup(Key::Period, Some(Key::Period), ctrl, true), run("selection.nextCorner"));
+    assert_eq!(lookup(Key::Period, Some(Key::Period), Modifiers { shift: true, ..mac_cmd }, true), run("home.increaseFontSize"));
     // Plain keys stay with the grid (typing, navigation).
     assert_eq!(lookup(Key::A, Some(Key::A), Modifiers::NONE, false), None);
     assert_eq!(lookup(Key::F2, Some(Key::F2), Modifiers::NONE, false), None);

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-02 · **Change:** minor (dragging the selection's border onto data asks before replacing it; 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
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-03 · **Change:** minor (Ctrl+. Next Corner of Selection; earlier: dragging the selection's border onto data asks before replacing it; 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
@@ -125,6 +125,7 @@ otherwise. Number-format and border keys match the physical key (Ctrl+Shift+4, w
 | — | Cmd+Shift+H, Cmd+Shift+R, Cmd+Shift+K / J, Control+L, Control+U | replace, sort, group / ungroup, Define Name, edit cell | **added** |
 | Alt+Shift+Right / Left | Option+Right / Left is next/previous sheet | group / ungroup | **added** |
 | Ctrl+Shift+* (Ctrl+Shift+8), Ctrl+Shift+Space | Cmd+Shift+Space | current region, select all | **added** |
+| Ctrl+. | Control+. | Next Corner of Selection: the active cell goes clockwise to the next corner and anchors there (`selection.nextCorner`, #1442) | **added** |
 | Ctrl+Shift+Home / End, Shift+Home | same | extend to A1 / last used cell / row start | **added** |
 | Ctrl+P | Cmd+P | print | **added** |
 | Ctrl+Shift+> / < | Cmd+Shift+> / < | font size | **added** |
@@ -237,6 +238,7 @@ scrollbar bugs 2–4 · pixel/feel pass against observed Excel 7–12.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-03 | minor | Ctrl+. (Control+. on a Mac): Next Corner of Selection, `selection.nextCorner`: the active cell moves clockwise to the next corner of the selected area, which stays selected, and becomes the anchor, as in Excel (#1442) |
 | 2026-11-02 | minor | Dragging the selection's border onto cells that hold data asks "There's already data here. Do you want to replace it?" (OK replaces, Cancel leaves the sheet and clipboard as they were) through the new `range.move` command (#3136); the row no longer claims Ctrl/Option copy and Shift insert for the border drag, which are not wired yet |
 | 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 |