diff --git a/crates/engine/src/cmd/effectcmd.rs b/crates/engine/src/cmd/effectcmd.rs
index 8010931a7..feee6913f 100644
--- a/crates/engine/src/cmd/effectcmd.rs
+++ b/crates/engine/src/cmd/effectcmd.rs
@@ -213,16 +213,15 @@ pub(crate) fn apply(s: &mut Session, p: &Value) -> Result<Value> {
             }
         }
     }
-    let mut index = 0;
     let ids = edit_effects(s, p, item, C, &label, "Apply Effect: select objects", 0, |fx, _| {
         fx.push(effect.clone());
-        index = fx.len() - 1;
         true
     })?;
     // The item the effect landed on in the object whose row the item is (the first selected object
-    // for the active item, which applies where it fits).
+    // for the active item, which applies where it fits), and the effect's index in that object.
     let first = ids.get(item.anchor(s, &ids)).and_then(|id| s.doc().ok()?.doc.node(*id));
     let landed = first.and_then(|n| item.effects_item(&n.appearance, C).ok().flatten());
+    let index = first.and_then(|n| n.appearance.effects_at(landed)).map_or(0, |fx| fx.len().saturating_sub(1));
     Ok(json!({ "ids": ids_json(&ids), "index": index, "item": landed }))
 }
 
diff --git a/crates/engine/src/tests/appearance.rs b/crates/engine/src/tests/appearance.rs
index e36871188..e1728c1ad 100644
--- a/crates/engine/src/tests/appearance.rs
+++ b/crates/engine/src/tests/appearance.rs
@@ -513,6 +513,27 @@ fn edits_change_the_active_row_of_the_first_selected_object() {
     assert!(!e.contains("internal error"), "{e}");
 }
 
+/// `effect.apply`'s reply names the new effect by its index in the object whose row `item` is,
+/// also when the objects painted after it already have effects there.
+#[test]
+fn apply_reports_the_index_in_the_object_whose_row_it_names() {
+    let mut s = session();
+    let (a, b) = reversed_pair(&mut s);
+    let c = rect(&mut s, 350.0);
+    run(&mut s, "effect.apply", json!({"effect": "distort.twist", "item": 0}));
+    // b's red fill row is not shared, so each object's row 0 takes the effect: c's second one.
+    run(&mut s, "select.set", json!({"ids": [b.0, a.0, c.0]}));
+    run(&mut s, "appearance.setActiveItem", json!({"index": 0}));
+    let r = run(&mut s, "effect.apply", json!({"effect": "distort.twist"}));
+    assert_eq!(node(&s, c).appearance.items[0].effects().len(), 2);
+    assert_eq!((r["item"].clone(), r["index"].clone()), (json!(0), json!(0)), "b's row 0 holds one effect");
+    // An explicit item is a row of the first target, a, which paints below c.
+    run(&mut s, "select.set", json!({"ids": [c.0, a.0]}));
+    let r = run(&mut s, "effect.apply", json!({"effect": "distort.twist", "item": 0}));
+    assert_eq!(node(&s, c).appearance.items[0].effects().len(), 3);
+    assert_eq!((r["item"].clone(), r["index"].clone()), (json!(0), json!(1)), "a's row 0 holds two effects");
+}
+
 /// How many steps there are to undo and to redo, and whether the document has unsaved changes.
 fn history(s: &Session) -> (usize, usize, bool) {
     let st = s.doc().unwrap();