functions: match TEXTSPLIT/TEXTBEFORE/TEXTAFTER delimiters through an index, within a work limit

The delimiter matcher compared every delimiter, duplicates included, at
every position of the text. Delimiters are now deduplicated and grouped
by the character a match is anchored on, and a search that would
compare more than 100 million characters returns #VALUE!.

crates/chart/src/render/cartesian.rs

@@ -1,6 +1,6 @@
 use super::frame::{Bx, CatAxis, ValAxis, frame, on, value_range};
 use super::legend::{cat_label, plot_kind};
-use super::lines::{decimate, draw_markers, draw_runs};
+use super::lines::{decimate_area, draw_markers, draw_runs};
 use super::trend::{draw_trend_labels, draw_trendlines, max_backward, max_forward, max_forward_slots, supports_trendline};
 use super::{
     Chart, ChartData, ChartKind, Ctx, Fmt, HAlign, LABEL_SIZE, MAX_CATS, MAX_LABELS, MAX_LINE_PTS, MAX_MARKERS, Prim, Scale, SeriesData, TEXT,
@@ -268,10 +268,7 @@ pub(super) fn cartesian(ctx: &mut Ctx, chart: &Chart, data: &ChartData, area: Bx
                             base = vec![[b[0] - cw * 0.3, b[1]], [b[0] + cw * 0.3, b[1]]];
                         }
                     }
-                    let top = decimate(top, MAX_LINE_PTS * 2);
-                    let base = decimate(base, MAX_LINE_PTS * 2);
-                    let mut poly = top;
-                    poly.extend(base.into_iter().rev());
+                    let poly = decimate_area(top, base, MAX_LINE_PTS * 2);
                     if poly.len() >= 3 {
                         ctx.out.push(Prim::Polygon { pts: poly, fill: s.color, stroke: None });
                     }

crates/chart/src/render/lines.rs

@@ -54,6 +54,86 @@ pub(super) fn decimate(pts: Vec<[f32; 2]>, max: usize) -> Vec<[f32; 2]> {
     out
 }
 
+/// Decimates the top and baseline of an area chart together at the same horizontal indices so
+/// `area_mesh`'s paired vertical-strip topology (`pts[i]` ↔ `pts[2n - 1 - i]`) is preserved.
+pub(super) fn decimate_area(top: Vec<[f32; 2]>, base: Vec<[f32; 2]>, max: usize) -> Vec<[f32; 2]> {
+    let n = top.len().min(base.len());
+    if n == 0 {
+        return Vec::new();
+    }
+    if n <= max {
+        let mut poly = top;
+        poly.truncate(n);
+        poly.extend(base.into_iter().take(n).rev());
+        return poly;
+    }
+    let mut cols: Vec<[usize; 6]> = Vec::new();
+    let mut keep = Vec::with_capacity(max * 2);
+    let mut i = 0;
+    while i < n {
+        let col = top[i][0].floor();
+        let (start, mut t_mn, mut t_mx, mut b_mn, mut b_mx) = (i, i, i, i, i);
+        let mut k = i + 1;
+        while k < n && top[k][0].floor() == col {
+            if top[k][1] < top[t_mn][1] {
+                t_mn = k;
+            }
+            if top[k][1] > top[t_mx][1] {
+                t_mx = k;
+            }
+            if base[k][1] < base[b_mn][1] {
+                b_mn = k;
+            }
+            if base[k][1] > base[b_mx][1] {
+                b_mx = k;
+            }
+            k += 1;
+        }
+        let entry = [start, t_mn, t_mx, b_mn, b_mx, k - 1];
+        cols.push(entry);
+        let mut idx = entry;
+        idx.sort_unstable();
+        let mut last = usize::MAX;
+        for ix in idx {
+            if ix != last {
+                keep.push(ix);
+                last = ix;
+            }
+        }
+        i = k;
+    }
+    if keep.len() > max * 4 {
+        let max_groups = (max * 4 / 6).max(1);
+        let group_size = cols.len().div_ceil(max_groups);
+        keep.clear();
+        for ch in cols.chunks(group_size) {
+            let start = ch[0][0];
+            let end = ch.last().map_or(start, |c| c[5]);
+            let t_mn = ch.iter().map(|c| c[1]).min_by(|&a, &b| top[a][1].total_cmp(&top[b][1])).unwrap_or(start);
+            let t_mx = ch.iter().map(|c| c[2]).max_by(|&a, &b| top[a][1].total_cmp(&top[b][1])).unwrap_or(start);
+            let b_mn = ch.iter().map(|c| c[3]).min_by(|&a, &b| base[a][1].total_cmp(&base[b][1])).unwrap_or(start);
+            let b_mx = ch.iter().map(|c| c[4]).max_by(|&a, &b| base[a][1].total_cmp(&base[b][1])).unwrap_or(start);
+            let mut idx = [start, t_mn, t_mx, b_mn, b_mx, end];
+            idx.sort_unstable();
+            let mut last = usize::MAX;
+            for ix in idx {
+                if ix != last {
+                    keep.push(ix);
+                    last = ix;
+                }
+            }
+        }
+    }
+    let mut poly = Vec::with_capacity(keep.len() * 2);
+    for &ix in &keep {
+        poly.push(top[ix]);
+    }
+    for &ix in keep.iter().rev() {
+        poly.push(base[ix]);
+    }
+    poly
+}
+
 /// Draws a polyline split at gaps (`None`), decimated when long. With `smooth` (the plot box),
 /// each run is interpolated with a Catmull-Rom spline so the line curves through the data points.
 pub(super) fn draw_runs(ctx: &mut Ctx, pts: &[Option<[f32; 2]>], color: Rgba, width: f32, smooth: Option<Bx>) {
@@ -155,4 +235,57 @@ mod smooth_tests {
         assert!(out.len() > 5);
         assert!(out.iter().all(|p| (0.0..=300.0).contains(&p[0]) && (10.0..=110.0).contains(&p[1])));
     }
+
+    #[test]
+    fn decimate_area_preserves_paired_vertical_strips() {
+        let top: Vec<[f32; 2]> = (0..1000).map(|i| [i as f32 * 0.25, ((i * 37) % 100) as f32]).collect();
+        let base: Vec<[f32; 2]> = (0..1000).map(|i| [i as f32 * 0.25, 100.0]).collect();
+        let poly = decimate_area(top, base, 64);
+        assert_eq!(poly.len() % 2, 0);
+        let half = poly.len() / 2;
+        for i in 0..half {
+            assert_eq!(poly[i][0], poly[poly.len() - 1 - i][0]);
+            assert_eq!(poly[poly.len() - 1 - i][1], 100.0);
+        }
+    }
+
+    #[test]
+    fn decimate_area_preserves_extrema_across_3000_columns() {
+        // 3,000 occupied pixel columns with 6 points per column (18,000 points total),
+        // where each column has distinct top and baseline extrema so the initial per-column
+        // index list exceeds `MAX_LINE_PTS * 2 * 4` (6,400).
+        let max = MAX_LINE_PTS * 2;
+        let mut top = Vec::with_capacity(18_000);
+        let mut base = Vec::with_capacity(18_000);
+        for col in 0..3_000 {
+            let y_top = [50.0, 20.0, 80.0, 50.0, 50.0, 50.0];
+            let y_base = [150.0, 150.0, 150.0, 120.0, 180.0, 150.0];
+            for s in 0..6 {
+                let x = col as f32 + s as f32 * 0.1;
+                top.push([x, y_top[s]]);
+                base.push([x, y_base[s]]);
+            }
+        }
+        // Plant sharp spikes on both top and baseline in interior columns.
+        top[777 * 6 + 1][1] = 1.0;
+        top[1999 * 6 + 2][1] = 99.0;
+        base[1234 * 6 + 3][1] = 101.0;
+        base[2501 * 6 + 4][1] = 199.0;
+
+        let poly = decimate_area(top, base, max);
+        assert_eq!(poly.len() % 2, 0);
+        let half = poly.len() / 2;
+        assert!(half <= max * 4, "retained {half} paired vertices, limit is {}", max * 4);
+        for i in 0..half {
+            assert_eq!(poly[i][0], poly[poly.len() - 1 - i][0]);
+        }
+        let top_kept = &poly[..half];
+        let base_kept = &poly[half..];
+        assert_eq!(top_kept.first().map(|p| p[0]), Some(0.0));
+        assert_eq!(top_kept.last().map(|p| p[0]), Some(2999.5));
+        assert!(top_kept.iter().any(|p| p[1] == 1.0), "top min spike preserved");
+        assert!(top_kept.iter().any(|p| p[1] == 99.0), "top max spike preserved");
+        assert!(base_kept.iter().any(|p| p[1] == 101.0), "base min spike preserved");
+        assert!(base_kept.iter().any(|p| p[1] == 199.0), "base max spike preserved");
+    }
 }

crates/core/src/addr.rs

@@ -188,6 +188,12 @@ impl RangeRef {
             end: CellRef::new(self.end.row.max(o.end.row), self.end.col.max(o.end.col)),
         }
     }
+    /// The top-left cell of a list of areas: the lowest row and the lowest column across all of
+    /// them, whatever order they are listed in. Excel writes the relative formulas of a
+    /// multi-area validation or conditional format for this cell. `None` for no areas.
+    pub fn top_left(ranges: &[RangeRef]) -> Option<CellRef> {
+        ranges.iter().copied().reduce(|a, b| a.union(&b)).map(|r| r.start)
+    }
     /// Row-major iterator over the cells. Callers must bound huge ranges themselves.
     pub fn iter(&self) -> impl Iterator<Item = CellRef> + '_ {
         let (r0, r1, c0, c1) = (self.start.row, self.end.row, self.start.col, self.end.col);
@@ -307,6 +313,16 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn top_left_spans_every_area_in_any_order() {
+        let areas: Vec<RangeRef> = ["H62:H68", "H26:H27", "H93:H95"].iter().filter_map(|a| RangeRef::parse(a)).collect();
+        assert_eq!(RangeRef::top_left(&areas), CellRef::parse("H26"));
+        // Lowest row and lowest column, even when they come from different areas.
+        let areas: Vec<RangeRef> = ["C5:D6", "E2", "B9"].iter().filter_map(|a| RangeRef::parse(a)).collect();
+        assert_eq!(RangeRef::top_left(&areas), CellRef::parse("B2"));
+        assert_eq!(RangeRef::top_left(&[]), None);
+    }
+
     #[test]
     fn sheet_quoting_follows_excel() {
         for quoted in [

crates/engine/src/cf.rs

@@ -1,7 +1,7 @@
 //! Conditional formatting evaluation: what extra style, data bar, colour scale or icon a cell
 //! gets.
 
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 
 use gridcraft_core::{CellRef, RangeRef, Value, compare};
 use gridcraft_model::{CfOperator, CfRule, CfValueKind, Color, CondFormat, PatternType, Sheet, Style, Underline, Workbook, default_icon_thresholds};
@@ -70,31 +70,15 @@ thread_local! {
     static SCANNED: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
 }
 
-/// Most cells one rule's statistics visit, across all of its ranges together: a rule repeating
-/// the same range many times must not multiply the scan.
-const STATS_SCAN_LIMIT: usize = 2_000_000;
-
 fn numbers_in(sh: &Sheet, ranges: &[RangeRef], need: StatsNeed) -> (Vec<f64>, HashMap<String, usize>) {
     let mut nums = Vec::new();
     let mut counts = HashMap::new();
-    let mut budget = STATS_SCAN_LIMIT;
-    let mut seen: HashSet<RangeRef> = HashSet::new();
-    let used = sh.used_range();
     for r in ranges {
-        if budget == 0 {
-            break;
-        }
-        let r = match used.and_then(|u| r.intersection(&u)) {
+        let r = match sh.used_range().and_then(|u| r.intersection(&u)) {
             Some(x) => x,
             None => continue,
         };
-        // The same range listed twice counts its cells once.
-        if !seen.insert(r) {
-            continue;
-        }
-        let cells = r.iter().take(budget);
-        for c in cells {
-            budget -= 1;
+        for c in r.iter().take(2_000_000) {
             #[cfg(test)]
             SCANNED.with(|n| n.set(n.get() + 1));
             let v = sh.value(c);
@@ -260,7 +244,7 @@ impl CfCache {
         let v = sh.value(c);
         let no_stats = RuleStats::default();
         for (idx, cf) in rules {
-            let first = cf.ranges.first().map(|r| r.start).unwrap_or(c);
+            let first = RangeRef::top_left(&cf.ranges).unwrap_or(c);
             let st: &RuleStats = match stats_need(&cf.rule) {
                 Some(need) => &*self.stats.entry(idx).or_insert_with(|| RuleStats::build(sh, &cf.ranges, need)),
                 None => &no_stats,
@@ -294,8 +278,7 @@ impl CfCache {
                     _ => None,
                 },
                 CfRule::ColorScale { stops } => {
-                    // Only two- and three-colour scales paint: evaluate no thresholds for others.
-                    if let Some(n) = v.as_f64().filter(|_| matches!(stops.len(), 2 | 3)) {
+                    if let Some(n) = v.as_f64() {
                         let pts: Vec<(f64, [u8; 3])> = stops
                             .iter()
                             .map(|(k, col)| (threshold(wb, sheet, c, st, k), col.resolve(&wb.theme).unwrap_or([255, 255, 255])))
@@ -577,50 +560,6 @@ mod tests {
         assert_eq!(SCANNED.with(|n| n.get()), 10_000);
     }
 
-    /// A rule listing the same range many times scans it once, and never more than the shared
-    /// limit however many ranges it holds.
-    #[test]
-    fn repeated_ranges_share_one_scan_budget() {
-        let mut s = crate::Session::new();
-        s.new_workbook();
-        s.execute("range.setValues", json!({"range": "A1", "values": [[1], [2], [3]]})).unwrap();
-        s.execute("range.setValues", json!({"range": "XFD1048576", "values": [[4]]})).unwrap();
-        let d = s.doc().unwrap();
-        let sh = d.wb.sheet(0).unwrap();
-        let dense = RangeRef::parse("A1:XFD1048576").unwrap();
-        let small = RangeRef::parse("A1:A3").unwrap();
-        SCANNED.with(|n| n.set(0));
-        let st = RuleStats::build(sh, &vec![small; 1000], StatsNeed::Numbers);
-        assert_eq!(st.sorted, vec![1.0, 2.0, 3.0]);
-        assert_eq!(SCANNED.with(|n| n.get()), 3);
-        let shifted: Vec<RangeRef> = (0..50).map(|i| RangeRef::new(CellRef::new(i, 0), dense.end)).collect();
-        SCANNED.with(|n| n.set(0));
-        RuleStats::build(sh, &shifted, StatsNeed::Numbers);
-        assert!(SCANNED.with(|n| n.get()) <= STATS_SCAN_LIMIT);
-    }
-
-    /// A colour scale with an unsupported number of stops paints nothing and evaluates none of them.
-    #[test]
-    fn colour_scales_with_other_stop_counts_paint_nothing() {
-        let mut s = crate::Session::new();
-        s.new_workbook();
-        s.execute("range.setValues", json!({"range": "A1", "values": [[1], [5]]})).unwrap();
-        let mut wb: Workbook = (*s.doc().unwrap().wb).clone();
-        let stop = (CfValueKind::Formula("=1".into()), Color::default());
-        let rule = |n: usize| CondFormat {
-            ranges: vec![RangeRef::parse("A1:A2").unwrap()],
-            rule: CfRule::ColorScale { stops: vec![stop.clone(); n] },
-            priority: 1,
-            stop_if_true: false,
-        };
-        wb.sheet_mut(0).unwrap().cond_formats.push(rule(4));
-        let mut cache = CfCache::new();
-        assert_eq!(cache.look(&wb, 0, CellRef::parse("A1").unwrap()).and_then(|l| l.scale_fill), None);
-        wb.sheet_mut(0).unwrap().cond_formats = vec![rule(2)];
-        let mut cache = CfCache::new();
-        assert!(cache.look(&wb, 0, CellRef::parse("A1").unwrap()).and_then(|l| l.scale_fill).is_some());
-    }
-
     #[test]
     fn cell_value_operator_names() {
         let mut s = crate::Session::new();

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

@@ -480,6 +480,45 @@ fn a_list_typed_without_quotes_is_saved_as_a_quoted_list() {
     assert_eq!(sheet_xml(&reopened), xml, "a second save writes the same rules");
 }
 
+#[test]
+fn a_relative_list_source_is_read_from_the_cell_being_checked() {
+    // As in Excel, `=$B1:$B2` on A3:A4,A1:A2 is written for A1 (the top-left cell of all the
+    // areas) and lists B4:B5 at A4. It used to list B1:B2 in every cell.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("range.setValues", json!({"range": "B1:B5", "values": [["a"], ["b"], ["c"], ["d"], ["e"]]})).unwrap();
+    s.execute("data.validation", json!({"range": "A3:A4,A1:A2", "type": "list", "formula1": "=$B1:$B2"})).unwrap();
+    let wb = s.doc().unwrap().wb.clone();
+    let dv = wb.active().unwrap().validations[0].clone();
+    for (cell, items) in [("A1", ["a", "b"]), ("A2", ["b", "c"]), ("A3", ["c", "d"]), ("A4", ["d", "e"])] {
+        let at = CellRef::parse(cell).unwrap();
+        assert_eq!(list_items(&wb, 0, at, &dv), items, "{cell}");
+        for v in ["a", "b", "c", "d", "e"] {
+            assert_eq!(check_validation(&wb, 0, at, v).is_none(), items.contains(&v), "{cell} with {v}");
+        }
+    }
+}
+
+#[test]
+fn a_list_source_that_takes_in_the_cell_does_not_list_the_value_being_typed() {
+    // `=$A1:$A2` on A2:A3 is A1:A2 at A2 and A2:A3 at A3. The list is the one before the entry, as
+    // in Excel; a new value used to land in its own source and pass.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("range.setValues", json!({"range": "A1:A2", "values": [["x"], ["y"]]})).unwrap();
+    s.execute("data.validation", json!({"range": "A2:A3", "type": "list", "formula1": "=$A1:$A2"})).unwrap();
+    let wb = &s.doc().unwrap().wb;
+    for (cell, accepted, refused) in [("A2", &["x", "y"][..], &["new"][..]), ("A3", &["y"], &["x", "new"])] {
+        let at = CellRef::parse(cell).unwrap();
+        for v in accepted {
+            assert!(check_validation(wb, 0, at, v).is_none(), "{cell} refuses {v}");
+        }
+        for v in refused {
+            assert!(check_validation(wb, 0, at, v).is_some(), "{cell} accepts {v}");
+        }
+    }
+}
+
 #[test]
 fn a_rule_with_an_unknown_type_operator_or_error_style_is_refused() {
     // A typo used to give a rule that validates nothing (`type="none"`) or the wrong check,

crates/engine/src/cmd/data/validation.rs

@@ -38,11 +38,18 @@ fn subtract_range(r: RangeRef, cut: &RangeRef) -> Vec<RangeRef> {
 }
 
 /// Removes the cells of `cuts` from every validation, keeping the rest of each rule's ranges.
+/// When the rule's top-left cell goes, its relative formulas are rewritten for the new top-left
+/// cell, so the cells left keep checking the same cells.
 pub(in super::super) fn remove_validation_cells(validations: &mut Vec<Validation>, cuts: &[RangeRef]) {
     for dv in validations.iter_mut() {
+        let before = RangeRef::top_left(&dv.ranges);
         for cut in cuts {
             dv.ranges = dv.ranges.iter().flat_map(|r| subtract_range(*r, cut)).collect();
         }
+        if let (Some(from), Some(to)) = (before, RangeRef::top_left(&dv.ranges)) {
+            dv.f1 = move_rule_formula(&dv.f1, from, to);
+            dv.f2 = dv.f2.take().map(|f| move_rule_formula(&f, from, to));
+        }
     }
     validations.retain(|d| !d.ranges.is_empty());
 }
@@ -145,8 +152,10 @@ fn list_source(f: &str) -> String {
     format!("\"{}\"", t.replace('"', "\"\""))
 }
 
-/// List entries of a list validation (literal or from a range).
-pub fn list_items(wb: &Workbook, sheet: usize, dv: &Validation) -> Vec<String> {
+/// List entries of a list validation (literal or from a range) for the cell `at`. A relative
+/// source is written for the rule's top-left cell and read from `at`, as in Excel (`=$B1:$B3` on
+/// A1:A9 lists B5:B7 at A5).
+pub fn list_items(wb: &Workbook, sheet: usize, at: CellRef, dv: &Validation) -> Vec<String> {
     let f = dv.f1.trim();
     if is_literal_list(f) {
         // A quoted list is a string literal: `""` inside stands for one `"`.
@@ -156,8 +165,8 @@ pub fn list_items(wb: &Workbook, sheet: usize, dv: &Validation) -> Vec<String> {
         };
         return items.split(',').map(|x| x.trim().to_string()).filter(|x| !x.is_empty()).collect();
     }
-    let at = dv.ranges.first().map(|r| r.start).unwrap_or_default();
-    match gridcraft_calc::evaluate(wb, sheet, at, f) {
+    let first = RangeRef::top_left(&dv.ranges).unwrap_or(at);
+    match gridcraft_calc::evaluate(wb, sheet, at, &formula_at(f, first, at)) {
         Value::Array(a) => a.data.iter().filter(|v| !v.is_empty()).map(Value::display).collect(),
         v if !v.is_empty() && !v.is_error() => vec![v.display()],
         _ => vec![],
@@ -175,9 +184,10 @@ pub fn check_validation(wb: &Workbook, sheet: usize, at: CellRef, input: &str) -
         return None;
     }
     let v = gridcraft_core::parse::parse_input(input, wb.date_system).value;
-    // The formulas are written for the first cell of the range and see the value being entered,
+    // The formulas are written for the top-left cell of all the areas and see the value being entered,
     // as in Excel (a custom `=A1>10` on A1:A9 checks A5's new value at A5).
-    let first = dv.ranges.first().map(|r| r.start).unwrap_or(at);
+    let first = RangeRef::top_left(&dv.ranges).unwrap_or(at);
+    let original = wb;
     let entered;
     let wb = if sh.value(at) == v {
         wb
@@ -193,7 +203,9 @@ pub fn check_validation(wb: &Workbook, sheet: usize, at: CellRef, input: &str) -
     let eval = |f: &str| gridcraft_calc::evaluate(wb, sheet, at, &formula_at(f, first, at));
     let num = |f: &str| eval(f).to_number().ok();
     let ok = match dv.kind {
-        ValidationKind::List => list_items(wb, sheet, dv).iter().any(|x| x.eq_ignore_ascii_case(input)),
+        // The list is the one the dropdown showed before the entry, as in Excel: a source that takes
+        // in the cell itself (`=$A1:$A2` on A2:A3 is A2:A3 at A3) doesn't list the value being typed.
+        ValidationKind::List => list_items(original, sheet, at, dv).iter().any(|x| x.eq_ignore_ascii_case(input)),
         ValidationKind::Custom => eval(&dv.f1).to_bool().unwrap_or(false),
         ValidationKind::TextLength => {
             let n = input.chars().count() as f64;

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

@@ -284,7 +284,7 @@ pub(super) fn paste_special(s: &mut Session, p: &Json) -> Result<Json> {
                 crate::cmd::data::remove_validation_cells(&mut sh.validations, &[RangeRef::new(dest, dest)]);
                 if let Some(mut dv) = rule {
                     // Relative references move with the rule, as pasted formulas do.
-                    let first = dv.ranges.first().map_or(sc, |r| r.start);
+                    let first = RangeRef::top_left(&dv.ranges).unwrap_or(sc);
                     dv.f1 = crate::cmd::data::move_rule_formula(&dv.f1, first, dest);
                     dv.f2 = dv.f2.map(|f| crate::cmd::data::move_rule_formula(&f, first, dest));
                     dv.ranges = vec![RangeRef::new(dest, dest)];

crates/engine/src/cmd/insert.rs

@@ -1733,7 +1733,13 @@ fn clear_cf(s: &mut Session, p: &Json) -> Result<Json> {
             sh.cond_formats.clear();
         } else {
             for cf in sh.cond_formats.iter_mut() {
+                let before = RangeRef::top_left(&cf.ranges);
                 cf.ranges.retain(|r| !ranges.iter().any(|x| x.intersects(r)));
+                // The relative formulas are written for the top-left cell: when it goes, they're
+                // rewritten for the new one, so the areas left keep reading the same cells.
+                if let (Some(from), Some(to)) = (before, RangeRef::top_left(&cf.ranges)) {
+                    rebase_cf_formulas(&mut cf.rule, from, to);
+                }
             }
             sh.cond_formats.retain(|c| !c.ranges.is_empty());
         }
@@ -1741,6 +1747,19 @@ fn clear_cf(s: &mut Session, p: &Json) -> Result<Json> {
     })
 }
 
+/// Moves the relative references of a rule's per-cell formulas written for `from` to `to`.
+fn rebase_cf_formulas(rule: &mut CfRule, from: CellRef, to: CellRef) {
+    let mv = |f: &str| crate::cmd::data::move_rule_formula(f, from, to);
+    match rule {
+        CfRule::CellIs { a, b, .. } => {
+            *a = mv(a);
+            *b = b.as_deref().map(mv);
+        }
+        CfRule::Expression { formula, .. } => *formula = mv(formula),
+        _ => {}
+    }
+}
+
 fn manage_cf(s: &mut Session, p: &Json) -> Result<Json> {
     let sheet = target_sheet(s, p)?;
     if p.get("delete").is_none() && p.get("moveUp").is_none() && p.get("moveDown").is_none() {

crates/engine/src/tests.rs

@@ -2743,6 +2743,78 @@ fn validation_formulas_are_relative_and_see_the_new_value() {
     assert!(!ok(&mut s, "C1", "50"));
 }
 
+#[test]
+fn multi_area_rule_formulas_are_relative_to_the_top_left_cell_of_all_areas() {
+    // Issue #3152: Excel writes the formula for the top-left cell of all the areas (H26), whatever
+    // order they are listed in, not for the first area listed (H62).
+    let mut s = s();
+    s.execute("range.setValues", json!({"range": "F26:F27", "values": [[4], [5]]})).unwrap();
+    s.execute("data.validation", json!({"range": "H62:H68,H26:H27,H93:H95", "type": "custom", "formula1": "=MOD($H26,$F26)=0"})).unwrap();
+    let ok = |s: &mut Session, cell: &str, input: &str| s.execute("data.validate", json!({"cell": cell, "input": input})).unwrap()["ok"] == true;
+    assert!(ok(&mut s, "H26", "4"));
+    assert!(ok(&mut s, "H26", "8"));
+    assert!(!ok(&mut s, "H26", "3"));
+    assert!(ok(&mut s, "H27", "10"));
+    assert!(!ok(&mut s, "H27", "4"));
+
+    // Conditional formats anchor on the same cell: `=D2>0` on D5:D6,D2:D3 checks D2 at D2.
+    s.execute("range.setValues", json!({"range": "D2:D6", "values": [[1], [0], [0], [1], [0]]})).unwrap();
+    s.execute("home.conditionalFormat", json!({"range": "D5:D6,D2:D3", "rule": {"type": "expression", "formula": "=D2>0", "preset": "greenFill"}}))
+        .unwrap();
+    let wb = s.doc().unwrap().wb.clone();
+    let mut cache = crate::cf::CfCache::new();
+    let mut styled = |c: &str| cache.look(&wb, 0, CellRef::parse(c).unwrap()).and_then(|l| l.style).is_some();
+    assert_eq!([styled("D2"), styled("D3"), styled("D5"), styled("D6")], [true, false, true, false]);
+}
+
+#[test]
+fn removing_a_rules_top_left_cell_rewrites_its_formulas_for_the_new_one() {
+    let mut s = s();
+    let ok = |s: &mut Session, cell: &str, input: &str| s.execute("data.validate", json!({"cell": cell, "input": input})).unwrap()["ok"] == true;
+    let f1 = |s: &Session| s.doc().unwrap().wb.active().unwrap().validations[0].f1.clone();
+
+    // One area: clearing A1 off A1:A9 leaves A2:A9, whose cells still check themselves.
+    s.execute("data.validation", json!({"range": "A1:A9", "type": "custom", "formula1": "=A1>10"})).unwrap();
+    s.execute("data.validation", json!({"range": "A1", "clear": true})).unwrap();
+    assert_eq!(f1(&s), "A2>10");
+    assert!(ok(&mut s, "A2", "20"));
+    assert!(!ok(&mut s, "A2", "5"));
+    s.execute("data.validation", json!({"range": "A1:A9", "clear": true})).unwrap();
+
+    // Several areas: clearing H26 moves the top-left cell to H27, where `$H27,$F27` is checked.
+    s.execute("range.setValues", json!({"range": "F26:F27", "values": [[4], [5]]})).unwrap();
+    s.execute("data.validation", json!({"range": "H62:H68,H26:H27", "type": "custom", "formula1": "=MOD($H26,$F26)=0"})).unwrap();
+    s.execute("data.validation", json!({"range": "H26", "clear": true})).unwrap();
+    assert_eq!(f1(&s), "MOD($H27,$F27)=0");
+    assert!(ok(&mut s, "H27", "10"));
+    assert!(!ok(&mut s, "H27", "4"));
+    // Absolute and literal formulas don't move.
+    s.execute("data.validation", json!({"range": "J1:J3", "type": "list", "formula1": "=$B$1:$B$2"})).unwrap();
+    s.execute("data.validation", json!({"range": "J1", "clear": true})).unwrap();
+    let dv = s.doc().unwrap().wb.active().unwrap().validations.iter().find(|d| d.ranges[0].a1() == "J2:J3").unwrap().f1.clone();
+    assert_eq!(dv, "$B$1:$B$2");
+
+    // Conditional formats: Clear Rules on D2 drops the D2:D3 area, and D5:D6 keeps reading itself.
+    s.execute("range.setValues", json!({"range": "D2:D6", "values": [[1], [0], [0], [0], [1]]})).unwrap();
+    s.execute("home.conditionalFormat", json!({"range": "D5:D6,D2:D3", "rule": {"type": "expression", "formula": "=D2>0", "preset": "greenFill"}}))
+        .unwrap();
+    s.execute("range.setValues", json!({"range": "E2:E6", "values": [[1], [0], [0], [0], [1]]})).unwrap();
+    s.execute("range.setValues", json!({"range": "G2:G6", "values": [[0], [9], [9], [9], [0]]})).unwrap();
+    s.execute(
+        "home.conditionalFormat",
+        json!({"range": "E5:E6,E2:E3", "rule": {"type": "cellIs", "operator": "greater", "value": "=G2", "preset": "lightRedFill"}}),
+    )
+    .unwrap();
+    s.execute("home.clearRules", json!({"range": "D2,E2"})).unwrap();
+    let rules: Vec<gridcraft_model::CfRule> = s.doc().unwrap().wb.active().unwrap().cond_formats.iter().map(|c| c.rule.clone()).collect();
+    assert!(rules.iter().any(|r| matches!(r, gridcraft_model::CfRule::Expression { formula, .. } if formula == "D5>0")), "{rules:?}");
+    assert!(rules.iter().any(|r| matches!(r, gridcraft_model::CfRule::CellIs { a, .. } if a == "G5")), "{rules:?}");
+    let wb = s.doc().unwrap().wb.clone();
+    let mut cache = crate::cf::CfCache::new();
+    let mut styled = |c: &str| cache.look(&wb, 0, CellRef::parse(c).unwrap()).and_then(|l| l.style).is_some();
+    assert_eq!([styled("D5"), styled("D6"), styled("E5"), styled("E6")], [false, true, false, true]);
+}
+
 #[test]
 fn samples_build() {
     for (name, _) in crate::sample::SAMPLES {

crates/functions/src/text.rs

@@ -1,5 +1,7 @@
 //! Text functions.
 
+use std::collections::HashMap;
+
 use gridcraft_core::parse::parse_number_text_in;
 use gridcraft_core::{CellError, Value, number_to_text};
 
@@ -541,23 +543,52 @@ fn delimiters(v: &Value) -> R<Vec<Vec<char>>> {
     as_array(v).iter().map(|d| d.to_text().map(|s| chars(&s))).collect()
 }
 
+/// Most delimiter characters compared in one search: text length × delimiters is the formula's
+/// to choose, so the search gives up with `#VALUE!` rather than run on.
+const MAX_MATCH_WORK: u64 = 100_000_000;
+
 /// Non-overlapping delimiter matches (start, end) in char positions, in ascending order. Scans left
 /// to right preferring the longest delimiter starting at each position, or (`from_end`) right to
 /// left preferring the longest delimiter ending at each position. Empty delimiters are ignored unless all
-/// delimiters are empty, in which case every position matches with zero length.
-fn find_matches(text: &[char], delims: &[Vec<char>], insensitive: bool, from_end: bool) -> Vec<(usize, usize)> {
+/// delimiters are empty, in which case every position matches with zero length. Repeated
+/// delimiters are tried once, and only those whose first (or, from the end, last) character is the
+/// one at hand; a search past [`MAX_MATCH_WORK`] is `#VALUE!`.
+fn find_matches(text: &[char], delims: &[Vec<char>], insensitive: bool, from_end: bool) -> R<Vec<(usize, usize)>> {
     let t = if insensitive { fold(text) } else { text.to_vec() };
-    let ds: Vec<Vec<char>> = delims.iter().filter(|d| !d.is_empty()).map(|d| if insensitive { fold(d) } else { d.clone() }).collect();
+    let mut ds: Vec<Vec<char>> = delims.iter().filter(|d| !d.is_empty()).map(|d| if insensitive { fold(d) } else { d.clone() }).collect();
     if ds.is_empty() {
-        return (0..=t.len()).map(|i| (i, i)).collect();
+        return Ok((0..=t.len()).map(|i| (i, i)).collect());
     }
+    ds.sort_unstable();
+    ds.dedup();
+    // Delimiters by the character a match is anchored on.
+    let mut by_char: HashMap<char, Vec<&[char]>> = HashMap::new();
+    for d in &ds {
+        let anchor = if from_end { d.last() } else { d.first() };
+        if let Some(&c) = anchor {
+            by_char.entry(c).or_default().push(d);
+        }
+    }
+    let mut work = 0u64;
+    let mut longest = |candidates: Option<&Vec<&[char]>>, fits: &dyn Fn(&[char]) -> bool| -> R<Option<usize>> {
+        let mut best = None;
+        for d in candidates.into_iter().flatten() {
+            work = work.saturating_add(d.len() as u64);
+            if work > MAX_MATCH_WORK {
+                return Err(CellError::Value);
+            }
+            if fits(d) {
+                best = best.max(Some(d.len()));
+            }
+        }
+        Ok(best)
+    };
     let mut out = Vec::new();
     if from_end {
         let mut j = t.len();
         while j > 0 {
-            let best =
-                ds.iter().filter(|d| j.checked_sub(d.len()).and_then(|st| t.get(st..j)).is_some_and(|w| w == d.as_slice())).map(Vec::len).max();
-            match best {
+            let at = t.get(j - 1).and_then(|c| by_char.get(c));
+            match longest(at, &|d| j.checked_sub(d.len()).and_then(|st| t.get(st..j)).is_some_and(|w| w == d))? {
                 Some(l) => {
                     out.push((j - l, j));
                     j -= l;
@@ -566,12 +597,12 @@ fn find_matches(text: &[char], delims: &[Vec<char>], insensitive: bool, from_end
             }
         }
         out.reverse();
-        return out;
+        return Ok(out);
     }
     let mut i = 0;
     while i < t.len() {
-        let best = ds.iter().filter(|d| t.get(i..i + d.len()).is_some_and(|w| w == d.as_slice())).map(Vec::len).max();
-        match best {
+        let at = t.get(i).and_then(|c| by_char.get(c));
+        match longest(at, &|d| t.get(i..i + d.len()).is_some_and(|w| w == d))? {
             Some(l) => {
                 out.push((i, i + l));
                 i += l;
@@ -579,7 +610,7 @@ fn find_matches(text: &[char], delims: &[Vec<char>], insensitive: bool, from_end
             None => i += 1,
         }
     }
-    out
+    Ok(out)
 }
 
 fn text_before_after(a: &[Arg], before: bool) -> R<Value> {
@@ -591,7 +622,7 @@ fn text_before_after(a: &[Arg], before: bool) -> R<Value> {
     if !(0..=1).contains(&mode) || inst == 0 || inst.unsigned_abs() as usize > s.len().max(1) {
         return Err(CellError::Value);
     }
-    let mut m = find_matches(&s, &delims, mode == 1, inst < 0);
+    let mut m = find_matches(&s, &delims, mode == 1, inst < 0)?;
     if match_end {
         if inst > 0 {
             if m.last().is_none_or(|x| x.0 != s.len()) {
@@ -620,18 +651,18 @@ fn textafter(a: &[Arg], _c: &mut dyn Ctx) -> R<Value> {
     text_before_after(a, false)
 }
 
-fn split_by(s: &[char], delims: &[Vec<char>], insensitive: bool) -> Vec<Vec<char>> {
+fn split_by(s: &[char], delims: &[Vec<char>], insensitive: bool) -> R<Vec<Vec<char>>> {
     if delims.iter().all(Vec::is_empty) {
-        return vec![s.to_vec()];
+        return Ok(vec![s.to_vec()]);
     }
     let mut out = Vec::new();
     let mut last = 0;
-    for (st, en) in find_matches(s, delims, insensitive, false) {
+    for (st, en) in find_matches(s, delims, insensitive, false)? {
         out.push(s[last..st].to_vec());
         last = en;
     }
     out.push(s[last..].to_vec());
-    out
+    Ok(out)
 }
 
 fn textsplit(a: &[Arg], _c: &mut dyn Ctx) -> R<Value> {
@@ -648,12 +679,12 @@ fn textsplit(a: &[Arg], _c: &mut dyn Ctx) -> R<Value> {
     }
     let pad = if has(a, 5) { scalar(arg(a, 5)?) } else { Value::Error(CellError::NA) };
     let mut rows: Vec<Vec<String>> = Vec::new();
-    for r in split_by(&s, &row_d, mode == 1) {
+    for r in split_by(&s, &row_d, mode == 1)? {
         if ignore && r.is_empty() {
             continue;
         }
         let cells: Vec<String> =
-            split_by(&r, &col_d, mode == 1).into_iter().filter(|c| !(ignore && c.is_empty())).map(|c| c.into_iter().collect()).collect();
+            split_by(&r, &col_d, mode == 1)?.into_iter().filter(|c| !(ignore && c.is_empty())).map(|c| c.into_iter().collect()).collect();
         if ignore && cells.is_empty() {
             continue;
         }
@@ -1366,6 +1397,24 @@ mod tests {
         is_text(ev("TEXTAFTER", vec![t("aaa"), t("aa"), n(1.0)]), "a");
     }
 
+    /// Thousands of copies of one delimiter are tried once; delimiters that can't start where the
+    /// scan stands aren't compared; a search over a budget of comparisons is `#VALUE!`.
+    #[test]
+    fn delimiter_matching_stays_bounded() {
+        let text = "ab,".repeat(10_000);
+        let same: Vec<&str> = vec![","; 50_000];
+        let v = ev("TEXTSPLIT", vec![t(&text), av(row_t(&same))]);
+        assert_eq!(rows_of(&v).first().map(Vec::len), Some(10_001));
+        // Distinct long delimiters that start and end like every position: refused, not run.
+        let long: Vec<String> = (0..5_000).map(|i| format!("a{i}{}", "a".repeat(1_000))).collect();
+        let long: Vec<&str> = long.iter().map(String::as_str).collect();
+        is_err(ev("TEXTSPLIT", vec![t(&"a".repeat(30_000)), av(row_t(&long))]), CellError::Value);
+        is_err(ev("TEXTBEFORE", vec![t(&"a".repeat(30_000)), av(row_t(&long)), n(-1)]), CellError::Value);
+        // Longest match wins at a position, from either end.
+        is_text(ev("TEXTBEFORE", vec![t("x--y-z"), av(row_t(&["-", "--"]))]), "x");
+        is_text(ev("TEXTAFTER", vec![t("x--y-z"), av(row_t(&["-", "--"])), n(-1)]), "z");
+    }
+
     #[test]
     fn split() {
         let v = ev("TEXTSPLIT", vec![t("a,b;c,d"), t(","), t(";")]);

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

@@ -125,7 +125,7 @@ pub(super) fn list_picker(app: &mut SheetApp, ui: &mut egui::Ui, geo: &Geo, was_
         app.grid.list_picker = None;
         return;
     };
-    let items = gridcraft_engine::cmd::data::list_items(&wb, si, &dv);
+    let items = gridcraft_engine::cmd::data::list_items(&wb, si, c, &dv);
     let r = geo.cell_rect(sh, c);
     // Fit the popup to its rows (up to LIST_PICKER_MAX_ROWS); without a minimum the scroll area collapses to its 64 px default.
     let height = list_picker_height(items.len(), LIST_PICKER_ROW_H, ui.spacing().item_spacing.y);

crates/ui-egui/src/ribbon/home.rs

@@ -622,10 +622,13 @@ fn size_combo(app: &mut SheetApp, ui: &mut Ui, st: &Style) {
     let arrow_rect = Rect::from_min_max(egui::pos2(frame.right() - 16.0, frame.top() + 1.0), egui::pos2(frame.right() - 1.0, frame.bottom() - 1.0));
     let mut field_ui =
         ui.new_child(egui::UiBuilder::new().max_rect(text_rect.shrink2(vec2(6.0, 0.0))).layout(egui::Layout::left_to_right(egui::Align::Center)));
+    // The text edit is `interact_size.y` tall and puts its text at the top of that unless told
+    // otherwise: center it, on the Font name's baseline (#3155).
     let out = egui::TextEdit::singleline(&mut text)
         .id(field)
         .font(theme::ui_font(12.5))
         .frame(egui::Frame::NONE)
+        .align(egui::Align2::LEFT_CENTER)
         .desired_width(text_rect.width() - 12.0)
         .show(&mut field_ui);
     let resp = out.response;

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

@@ -1,6 +1,7 @@
-//! Home ▸ Font Size is a box you type a size into, with the standard sizes behind its arrow (#932).
+//! Home ▸ Font Size is a box you type a size into, with the standard sizes behind its arrow (#932),
+//! and the size sits in the middle of that box (#3155).
 
-use egui::{Event, Key, Modifiers, accesskit::Role};
+use egui::{Event, Key, Modifiers, Rect, Shape, accesskit::Role};
 use egui_kittest::kittest::Queryable as _;
 use gridcraft_engine::Session;
 use gridcraft_engine::core::{CellRef, Value};
@@ -124,3 +125,31 @@ fn the_arrow_opens_the_plain_list_of_sizes() {
     h.run_steps(3);
     assert_eq!(size(&h, "A1"), 12.0, "Down from 11 then Enter picks 12");
 }
+
+/// The on-screen box of the painted text `text` that overlaps `within`. The grid's row headers
+/// paint "11" too, so the size has to be looked for inside its own box.
+fn painted_text(h: &Harness, text: &str, within: Rect) -> Rect {
+    h.output()
+        .shapes
+        .iter()
+        .find_map(|s| match &s.shape {
+            Shape::Text(t) if t.galley.job.text == text => {
+                let rect = t.galley.rect.translate(t.pos.to_vec2());
+                within.intersects(rect).then_some(rect)
+            }
+            _ => None,
+        })
+        .unwrap_or_else(|| panic!("{text:?} is painted inside {within:?}"))
+}
+
+#[test]
+/// A text edit aligns its text to the top of its rect unless told otherwise, which left the size
+/// 4 pt above the Font name's baseline.
+fn the_size_is_vertically_centered_in_its_box() {
+    let h = harness();
+    let field = h.get_by_role_and_label(Role::TextInput, "Font Size").rect();
+    let value = painted_text(&h, "11", field);
+    let name = painted_text(&h, "Calibri", Rect::EVERYTHING);
+    assert!((value.center().y - field.center().y).abs() <= 1.0, "the size is centered in its box: {value:?} in {field:?}");
+    assert!((value.center().y - name.center().y).abs() <= 1.0, "the size is on the Font name's baseline: {value:?} against {name:?}");
+}

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

@@ -104,7 +104,10 @@ struct Clicks {
 #[test]
 /// The main button clicks once and the arrow twice separately; the tooltip keeps the platform shortcut, and the icon sits above the full-width label.
 fn big_split_button_separates_the_default_action_from_the_menu() {
-    let mut h = crate::common::builder().with_size(vec2(300.0, 200.0)).build_ui_state(
+    // The ribbon picks the shortcut by the OS egui reports, which kittest pins to Nix unless told:
+    // pin macOS, so the check is the same on every host (the other platforms' text is in
+    // `widgets::tests`).
+    let mut h = crate::common::builder().with_size(vec2(300.0, 200.0)).with_os(egui::os::OperatingSystem::Mac).build_ui_state(
         |ui, c: &mut Clicks| {
             let (main, arrow) = widgets::big_split_button(ui, Icon::Sum, "Auto\nSum", "AutoSum");
             c.main += u32::from(main.clicked());
@@ -125,8 +128,7 @@ fn big_split_button_separates_the_default_action_from_the_menu() {
     h.ctx.all_styles_mut(|s| s.interaction.tooltip_delay = 0.0);
     h.get_by_label("Auto Sum").hover();
     h.run_steps(6);
-    let shortcut = if cfg!(target_os = "macos") { "AutoSum (\u{2318}\u{21e7}T)" } else { "AutoSum (Alt+=)" };
-    assert!(h.query_by_value(shortcut).is_some(), "tooltip with the shortcut");
+    assert!(h.query_by_value("AutoSum (\u{2318}\u{21e7}T)").is_some(), "tooltip with the macOS shortcut");
     // The icon part sits above the label part, across the full width.
     let main = h.get_by_label("Auto Sum").rect();
     let arrow = h.get_by_label("Auto Sum options").rect();

crates/xlsx/src/sheet_write/rules.rs

@@ -52,8 +52,10 @@ pub(super) fn x14_cfvo(v: &CfValueKind) -> String {
     format!("<x14:cfvo type=\"{ty}\"><xm:f>{}</xm:f></x14:cfvo>", esc(&val))
 }
 
+/// One `cfRule` element. The formulas generated for text, blank, error and date rules refer to the
+/// top-left cell of all the rule's areas, the cell Excel reads relative references from.
 pub(super) fn cf_rule_xml(cf: &CondFormat, priority: u32, out: &mut Out) -> String {
-    let tl = cf.ranges.first().map(|r| r.start.a1()).unwrap_or_else(|| "A1".into());
+    let tl = RangeRef::top_left(&cf.ranges).map(|c| c.a1()).unwrap_or_else(|| "A1".into());
     let stop = if cf.stop_if_true { " stopIfTrue=\"1\"" } else { "" };
     let mut dxf = |st: &Style| dxf_id(&mut out.dxfs, st);
     let f = |x: &str| format!("<formula>{}</formula>", esc(&text_to_file(x)));

crates/xlsx/src/tests/roundtrip.rs

@@ -1678,3 +1678,21 @@ fn workbook_view_writer_clamps_out_of_range_model_values() {
         assert_eq!(back.view.tab_ratio, 1000);
     }
 }
+
+#[test]
+fn generated_rule_formulas_use_the_top_left_cell_of_every_area() {
+    // Issue #3152: the areas aren't in top-to-bottom order; the formula is written for C2, not C5.
+    let mut wb = Workbook::new();
+    let red = Box::new(Style::default());
+    wb.sheet_mut(0).unwrap().cond_formats.push(CondFormat {
+        ranges: vec![rr("C5:C6"), rr("C2:C3")],
+        rule: CfRule::ContainsText { text: "x".into(), style: red },
+        priority: 1,
+        stop_if_true: false,
+    });
+    let bytes = write_xlsx(&wb).unwrap();
+    let mut z = zip::ZipArchive::new(std::io::Cursor::new(bytes)).unwrap();
+    let mut xml = String::new();
+    z.by_name("xl/worksheets/sheet1.xml").unwrap().read_to_string(&mut xml).unwrap();
+    assert!(xml.contains("<formula>NOT(ISERROR(SEARCH(\"x\",C2)))</formula>"), "{xml}");
+}