diff --git a/crates/ui-egui/src/columns_dialog_tests.rs b/crates/ui-egui/src/columns_dialog_tests.rs
index fa6b677f..7737031c 100644
--- a/crates/ui-egui/src/columns_dialog_tests.rs
+++ b/crates/ui-egui/src/columns_dialog_tests.rs
@@ -12,6 +12,24 @@ fn harness() -> Harness<'static, SlideApp> {
     let mut s = Session::with_new();
     s.execute("shape.insert", &json!({"preset": "rect", "rect": [80.0, 80.0, 320.0, 160.0], "text": "Hello"})).unwrap();
     let _ = s.execute("text.exit", &json!({}));
+    harness_of(s)
+}
+
+/// Two text boxes with different columns, both selected: 2 columns 9 pt apart, and 3 columns
+/// 36 pt apart.
+fn two_boxes() -> Harness<'static, SlideApp> {
+    let mut s = Session::with_new();
+    let mut ids = Vec::new();
+    for (y, count, spacing) in [(80.0, 2, 9.0), (300.0, 3, 36.0)] {
+        ids.push(s.execute("shape.insert", &json!({"preset": "rect", "rect": [80.0, y, 320.0, 160.0], "text": "Hello"})).unwrap()["id"].clone());
+        let _ = s.execute("text.exit", &json!({}));
+        s.execute("format.columns", &json!({"count": count, "spacing": spacing})).unwrap();
+    }
+    s.execute("edit.select", &json!({"ids": ids})).unwrap();
+    harness_of(s)
+}
+
+fn harness_of(s: Session) -> Harness<'static, SlideApp> {
     let app = SlideApp::new(s, Services::default());
     let mut h = Harness::builder().with_size(egui::vec2(1440.0, 900.0)).with_step_dt(1.0 / 60.0).build_ui_state(
         |ui, app: &mut SlideApp| {
@@ -30,6 +48,47 @@ fn columns_of(h: &Harness<'_, SlideApp>) -> (Option<u32>, Option<f64>) {
     (body.columns, body.col_spacing)
 }
 
+fn columns_of_each(h: &Harness<'_, SlideApp>) -> Vec<(Option<u32>, Option<f64>)> {
+    let st = h.state().session.active().unwrap();
+    st.selected_shapes().iter().map(|sh| sh.text.as_ref().map(|t| (t.body.columns, t.body.col_spacing)).unwrap_or_default()).collect()
+}
+
+/// Opens the dialog on `h`'s selection, types `fields` into it and presses OK.
+fn ok_with(h: &mut Harness<'_, SlideApp>, fields: &[(&str, &str)]) {
+    h.state_mut().run("format.columns", json!({})).unwrap();
+    h.run_steps(2);
+    let d = h.state_mut().dialog.as_mut().unwrap();
+    for (key, value) in fields {
+        d.fields.insert((*key).into(), (*value).into());
+    }
+    h.get_by_label("OK").click_accesskit();
+    h.run_steps(2);
+    assert!(h.state().dialog.is_none(), "status {:?}", h.state().status);
+}
+
+/// With text boxes whose columns differ, the dialog shows the first one's values, and a field
+/// left as shown does not overwrite the others' own values.
+#[test]
+fn a_field_left_as_shown_keeps_each_text_box_s_own_value() {
+    let mut h = two_boxes();
+    assert_eq!(columns_of_each(&h), [(Some(2), Some(9.0)), (Some(3), Some(36.0))]);
+    ok_with(&mut h, &[("count", "4")]);
+    assert_eq!(columns_of_each(&h), [(Some(4), Some(9.0)), (Some(4), Some(36.0))], "Number only");
+
+    let mut h = two_boxes();
+    ok_with(&mut h, &[("spacing", "0.5")]);
+    assert_eq!(columns_of_each(&h), [(Some(2), Some(36.0)), (Some(3), Some(36.0))], "Spacing only");
+}
+
+#[test]
+fn ok_with_nothing_changed_closes_without_an_edit() {
+    let mut h = two_boxes();
+    let n = h.state().session.active().unwrap().history.undo.len();
+    ok_with(&mut h, &[]);
+    assert_eq!(h.state().session.active().unwrap().history.undo.len(), n);
+    assert_eq!(columns_of_each(&h), [(Some(2), Some(9.0)), (Some(3), Some(36.0))]);
+}
+
 fn field(h: &Harness<'_, SlideApp>, key: &str) -> Option<String> {
     h.state().dialog.as_ref().and_then(|d| d.fields.get(key).cloned())
 }
diff --git a/crates/ui-egui/src/dialogs.rs b/crates/ui-egui/src/dialogs.rs
index 3e994589..9ecbdd5c 100644
--- a/crates/ui-egui/src/dialogs.rs
+++ b/crates/ui-egui/src/dialogs.rs
@@ -2664,31 +2664,35 @@ fn grid_options(app: &mut SlideApp, ui: &mut Ui, d: &mut Dialog) -> bool {
     cancel
 }
 
-/// The Columns dialog's fields as `format.columns` params: Number and Spacing (inches, sent in points).
-/// A Spacing left as the dialog showed it sends the text box's own spacing, unrounded.
-fn columns_value(d: &Dialog, shown_spacing: &str) -> Result<Value, String> {
-    let count =
-        field_of(d, "count").trim().parse::<u32>().ok().filter(|n| (1..=16).contains(n)).ok_or("Number must be a whole number from 1 to 16")?;
-    let typed = field_of(d, "spacing");
-    if typed == shown_spacing
-        && let Some(pt) = d.params.get("spacing").and_then(Value::as_f64).filter(|v| v.is_finite())
-    {
-        return Ok(json!({"count": count, "spacing": pt}));
+/// The Columns dialog's changed fields as `format.columns` params: Number and Spacing (inches,
+/// sent in points). A field left as the dialog showed it is left out, so each selected text box
+/// keeps its own value; `None` when neither field changed.
+fn columns_value(d: &Dialog, shown_count: &str, shown_spacing: &str) -> Result<Option<Value>, String> {
+    let mut p = serde_json::Map::new();
+    let count = field_of(d, "count");
+    if count != shown_count {
+        let n = count.trim().parse::<u32>().ok().filter(|n| (1..=16).contains(n)).ok_or("Number must be a whole number from 1 to 16")?;
+        p.insert("count".into(), json!(n));
     }
-    let spacing = typed
-        .trim()
-        .trim_end_matches("in")
-        .trim_end_matches('"')
-        .trim()
-        .parse::<f64>()
-        .ok()
-        .filter(|v| v.is_finite() && (0.0..=22.0).contains(v))
-        .ok_or("Spacing must be from 0 to 22 inches")?;
-    Ok(json!({"count": count, "spacing": spacing * 72.0}))
+    let spacing = field_of(d, "spacing");
+    if spacing != shown_spacing {
+        let inches = spacing
+            .trim()
+            .trim_end_matches("in")
+            .trim_end_matches('"')
+            .trim()
+            .parse::<f64>()
+            .ok()
+            .filter(|v| v.is_finite() && (0.0..=22.0).contains(v))
+            .ok_or("Spacing must be from 0 to 22 inches")?;
+        p.insert("spacing".into(), json!(inches * 72.0));
+    }
+    Ok((!p.is_empty()).then_some(Value::Object(p)))
 }
 
 /// Columns: the number of columns in the text box and the space between them. OK applies one
-/// `format.columns` call; Cancel leaves the text box as it was.
+/// `format.columns` call with the fields that changed, or none when neither did; Cancel leaves
+/// the text box as it was.
 fn columns_dialog(app: &mut SlideApp, ui: &mut Ui, d: &mut Dialog) -> bool {
     let count = d.params.get("count").and_then(Value::as_u64).unwrap_or(1).to_string();
     let spacing = num_text(d.params.get("spacing").and_then(Value::as_f64).unwrap_or(0.0) / 72.0);
@@ -2700,8 +2704,12 @@ fn columns_dialog(app: &mut SlideApp, ui: &mut Ui, d: &mut Dialog) -> bool {
     }
     let (ok, cancel) = buttons(ui, "OK");
     if ok {
-        match columns_value(d, &spacing).and_then(|p| app.run("format.columns", p)) {
-            Ok(_) => return true,
+        let applied = columns_value(d, &count, &spacing).and_then(|p| match p {
+            Some(p) => app.run("format.columns", p).map(|_| ()),
+            None => Ok(()),
+        });
+        match applied {
+            Ok(()) => return true,
             Err(e) => {
                 d.fields.insert("error".into(), e);
                 return false;