diff --git a/crates/engine/src/cmd/keywords.rs b/crates/engine/src/cmd/keywords.rs
index 3d9492499..a3862b3b4 100644
--- a/crates/engine/src/cmd/keywords.rs
+++ b/crates/engine/src/cmd/keywords.rs
@@ -184,7 +184,11 @@ pub fn specs() -> Vec<CommandSpec> {
                 };
                 let ids = s.targets(p);
                 let all = !ids.is_empty()
-                    && ids.iter().all(|id| s.catalog.photo(*id).is_some_and(|ph| ph.meta.keywords.iter().any(|x| x.eq_ignore_ascii_case(&k))));
+                    && ids.iter().all(|id| {
+                        s.catalog
+                            .photo(*id)
+                            .is_some_and(|ph| ph.meta.keywords.iter().any(|x| lightcraft_catalog::keywords::same(&clean(x), &clean(&k))))
+                    });
                 let ids: Vec<u64> = ids.iter().map(|i| i.0).collect();
                 let key = if all { "removeKeywords" } else { "addKeywords" };
                 // applying from Recent Keywords mustn't reshuffle the numbers under the keys
diff --git a/crates/engine/src/tests_keyword_list.rs b/crates/engine/src/tests_keyword_list.rs
index 3d5e21666..3084fc122 100644
--- a/crates/engine/src/tests_keyword_list.rs
+++ b/crates/engine/src/tests_keyword_list.rs
@@ -170,3 +170,16 @@ fn keyword_actions_count_the_photos_they_change() {
     assert_eq!(s.execute("keyword.rename", &json!({"from": "Marriages", "to": "Weddings"})).unwrap()["changed"], 1);
     assert_eq!(s.execute("keyword.delete", &json!({"keyword": "weddings"})).unwrap()["changed"], 1);
 }
+
+/// ⌥1–⌥9 take a set's keyword off the selected photos when they all have it, whatever the case of
+/// any of its letters (the set has "ärzte", the photos "ÄRZTE" and "ärzte").
+#[test]
+fn a_set_keyword_toggles_whatever_its_case() {
+    let mut s = Session::with_demo();
+    let ids: Vec<u64> = s.visible_cloned().iter().take(2).map(|p| p.0).collect();
+    s.execute("photo.setMeta", &json!({"ids": [ids[0]], "keywords": ["ÄRZTE"]})).unwrap();
+    s.execute("photo.setMeta", &json!({"ids": [ids[1]], "keywords": ["ärzte"]})).unwrap();
+    s.execute("keyword.saveSet", &json!({"name": "Clinic", "keywords": ["ärzte"]})).unwrap();
+    s.execute("keyword.toggleFromSet", &json!({"index": 1, "ids": ids})).unwrap();
+    assert!(ids.iter().all(|id| keywords_of(&s, *id).is_empty()), "taken off both");
+}