diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index e60cf5cf8..da435b7d7 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -184,6 +184,10 @@ pub struct Interaction {
     pub label: String,
     pub photo: PhotoId,
     pub original: Arc<DevelopSettings>,
+    /// Whether an edit during the interaction changed the crop itself. If none did, the crop the
+    /// photo shows was fitted by Constrain Crop, and the final commit starts again from the original
+    /// crop, so Auto Sync carries the edit and not the active photo's fitted crop.
+    pub crop_edited: bool,
 }
 
 /// The most photos an edit may touch for the view to follow it photo by photo; a larger edit is worked out whole.
@@ -877,9 +881,11 @@ impl Session {
         // Auto Sync carries the edit as asked; each photo then fits its own crop (review of #1990)
         let requested = settings;
         let settings = Arc::new(self.fit_constrained_crop(id, requested.clone()));
-        if let Some(i) = &self.interaction
+        let crop_edited = self.develop_of(id).is_some_and(|d| d.crop.geometry != requested.crop.geometry);
+        if let Some(i) = &mut self.interaction
             && i.photo == id
         {
+            i.crop_edited |= crop_edited;
             return self.apply_silent(Op::SetDevelop { id, settings, label: label.into(), edited: Some(now) });
         }
         let mut ops = vec![self.develop_op(id, (*settings).clone(), label).ok_or(lightcraft_catalog::CatalogError::NoPhoto(id))?];
@@ -903,7 +909,7 @@ impl Session {
         let warp_changed = before.geometry != d.geometry
             || before.optics != d.optics
             || before.orientation != d.orientation
-            || before.disabled_sections != d.disabled_sections;
+            || ["geometry", "optics"].iter().any(|s| before.section_enabled(s) != d.section_enabled(s));
         let crop_edited = before.crop.geometry != d.crop.geometry;
         if !(turned_on || (warp_changed && !crop_edited)) {
             return d;
@@ -971,7 +977,7 @@ impl Session {
         }
         let id = self.active().ok_or_else(|| EngineError::Other("no active photo".into()))?;
         let original = self.develop_of(id).unwrap_or_default();
-        self.interaction = Some(Interaction { label: label.into(), photo: id, original });
+        self.interaction = Some(Interaction { label: label.into(), photo: id, original, crop_edited: false });
         Ok(())
     }
 
@@ -982,9 +988,15 @@ impl Session {
         if *cur == *i.original {
             return Ok(());
         }
-        // Restore the original silently, then commit the final value as one step.
+        // Restore the original silently, then commit the final value as one step. A crop nobody
+        // edited goes back to the original's: Constrain Crop fits it again for the final warp, and
+        // Auto Sync carries the edit, not the active photo's fitted crop (review of #1990).
         self.apply_silent(Op::SetDevelop { id: i.photo, settings: i.original.clone(), label: i.label.clone(), edited: None })?;
-        self.set_develop(i.photo, (*cur).clone(), &i.label)
+        let mut last = (*cur).clone();
+        if !i.crop_edited {
+            last.crop.geometry = i.original.crop.geometry;
+        }
+        self.set_develop(i.photo, last, &i.label)
     }
 
     pub fn cancel_interaction(&mut self) -> Result<()> {
diff --git a/crates/engine/src/tests_constrain_crop.rs b/crates/engine/src/tests_constrain_crop.rs
index 51dcee1c0..9f01ed05d 100644
--- a/crates/engine/src/tests_constrain_crop.rs
+++ b/crates/engine/src/tests_constrain_crop.rs
@@ -98,3 +98,50 @@ fn auto_sync_fits_each_photos_own_crop() {
     s.selection = crate::Selection { ids: vec![b], active: Some(b) };
     assert!(fits(&s), "and fits B's warp");
 }
+
+/// Review of #1990 (CodeRabbit): the same with a slider drag (an interaction), the path the
+/// window uses: the drag fits A's crop live, and its end must not carry that crop over to B.
+#[test]
+fn auto_sync_after_a_slider_drag_fits_each_photos_own_crop() {
+    let mut s = Session::with_demo();
+    let ids: Vec<_> = s.catalog.photos().take(2).map(|p| p.id).collect();
+    let (a, b) = (ids[0], ids[1]);
+    s.selection = crate::Selection { ids: vec![b], active: Some(b) };
+    s.execute("crop.set", &json!({"rect": [0.05, 0.1, 0.45, 0.5]})).unwrap();
+    constrain(&mut s, true);
+    s.selection = crate::Selection { ids: vec![a], active: Some(a) };
+    constrain(&mut s, true);
+    let b_before = s.develop_of(b).unwrap().crop.geometry.rect;
+    s.selection = crate::Selection { ids: vec![a, b], active: Some(a) };
+    s.execute("develop.autoSync", &json!({"on": true})).unwrap();
+    s.execute("develop.beginInteraction", &json!({"label": "Vertical"})).unwrap();
+    for v in [-20.0, -40.0, -60.0] {
+        vertical(&mut s, v);
+    }
+    s.execute("develop.endInteraction", &json!({})).unwrap();
+    let (da, db) = (s.develop_of(a).unwrap(), s.develop_of(b).unwrap());
+    assert_eq!((da.geometry.vertical, db.geometry.vertical), (-60.0, -60.0));
+    let b_after = db.crop.geometry.rect;
+    assert_ne!(b_after, da.crop.geometry.rect, "B keeps a crop of its own");
+    let inside = |r: Rect, o: Rect| r.x0 >= o.x0 - 1e-9 && r.y0 >= o.y0 - 1e-9 && r.x1 <= o.x1 + 1e-9 && r.y1 <= o.y1 + 1e-9;
+    assert!(inside(b_after, b_before), "{b_before:?} -> {b_after:?}");
+    for photo in [a, b] {
+        s.selection = crate::Selection { ids: vec![photo], active: Some(photo) };
+        assert!(fits(&s), "each crop fits its photo's warp");
+    }
+}
+
+/// Review of #1990 (CodeRabbit): only the Geometry and Optics eyes change the warp; turning
+/// another section's eye off leaves a crop drawn by hand as it is.
+#[test]
+fn an_unrelated_section_eye_leaves_a_hand_drawn_crop() {
+    let mut s = Session::with_demo();
+    constrain(&mut s, true);
+    vertical(&mut s, -60.0);
+    s.execute("crop.set", &json!({"rect": [0.0, 0.0, 1.0, 1.0]})).unwrap();
+    s.execute("develop.sectionEnabled", &json!({"section": "light", "enabled": false})).unwrap();
+    assert_eq!(crop(&s).rect, Rect::new(0.0, 0.0, 1.0, 1.0), "the Light eye is no warp change");
+    s.execute("develop.sectionEnabled", &json!({"section": "geometry", "enabled": false})).unwrap();
+    s.execute("develop.sectionEnabled", &json!({"section": "geometry", "enabled": true})).unwrap();
+    assert!(fits(&s), "the Geometry eye is one: the crop fits again");
+}