diff --git a/crates/ui-egui/src/lib.rs b/crates/ui-egui/src/lib.rs
index 4c5a7a681..ebff5dd11 100644
--- a/crates/ui-egui/src/lib.rs
+++ b/crates/ui-egui/src/lib.rs
@@ -3571,6 +3571,8 @@ mod ime_tests;
 #[cfg(test)]
 mod last_color_tests;
 #[cfg(test)]
+mod reflection_pane_tests;
+#[cfg(test)]
 mod replacefonts_tests;
 #[cfg(test)]
 mod reuse_picker_tests;
diff --git a/crates/ui-egui/src/panes.rs b/crates/ui-egui/src/panes.rs
index 74482f930..cb294a3b8 100644
--- a/crates/ui-egui/src/panes.rs
+++ b/crates/ui-egui/src/panes.rs
@@ -658,8 +658,14 @@ fn fx_slider(
         } else {
             ui.data_mut(|d| d.remove::<f64>(sid));
         }
+        // The slider rounds to whole numbers, which reads as a change for a value such as 55.000000000000007;
+        // acting on it would re-add an effect the pane just cleared.
+        let moved = v.round() != value.round();
         if r.drag_stopped() || r.lost_focus() || (r.changed() && !r.dragged()) {
             ui.data_mut(|d| d.remove::<f64>(sid));
+            if !moved {
+                return;
+            }
             run(app, "shape.effects", json!({key: {prop: v * scale}}));
         }
     });
diff --git a/crates/ui-egui/src/reflection_pane_tests.rs b/crates/ui-egui/src/reflection_pane_tests.rs
new file mode 100644
index 000000000..dbedd5242
--- /dev/null
+++ b/crates/ui-egui/src/reflection_pane_tests.rs
@@ -0,0 +1,43 @@
+//! Format Shape ▸ Effects (#1356): Reflection "None" clears the effect after another preset.
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+
+use egui_kittest::Harness;
+use egui_kittest::kittest::Queryable;
+use serde_json::json;
+
+use crate::{Services, SlideApp};
+use deckcraft_engine::Session;
+
+fn has_reflection(h: &Harness<'_, SlideApp>) -> bool {
+    let st = h.state().session.active().unwrap();
+    let id = *st.selection.shapes.first().unwrap();
+    st.shape(id).unwrap().effects.as_ref().is_some_and(|e| e.reflection.is_some())
+}
+
+#[test]
+fn reflection_none_clears_after_a_second_preset() {
+    let mut s = Session::with_new();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    let id = s.execute("shape.insert", &json!({"preset": "rect", "rect": [72.0, 36.0, 144.0, 108.0]})).unwrap()["id"].as_u64().unwrap();
+    s.execute("edit.select", &json!({"ids": [id]})).unwrap();
+    let mut app = SlideApp::new(s, Services::default());
+    app.ui.pane = Some("format".into());
+    app.ui.format_tab = "effects".into();
+    let mut h = Harness::builder().with_size(egui::vec2(1400.0, 900.0)).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    h.run_steps(3);
+    // The Shadow row has a "None" too; Reflection's is the later one.
+    for preset in ["Tight", "Half", "Full"] {
+        h.get_by_label(preset).click();
+        h.run_steps(4);
+        assert!(has_reflection(&h), "{preset} adds a reflection");
+    }
+    h.get_all_by_label("None").last().unwrap().click();
+    h.run_steps(4);
+    assert!(!has_reflection(&h), "None clears the reflection");
+}