diff --git a/crates/ui-egui/src/transform_tool.rs b/crates/ui-egui/src/transform_tool.rs
index 8e0bba1cfe..8c21361cd8 100644
--- a/crates/ui-egui/src/transform_tool.rs
+++ b/crates/ui-egui/src/transform_tool.rs
@@ -559,14 +559,18 @@ pub fn commit(app: &mut PhotocraftApp) {
 }
 
 /// A transform whose layer or document went away (undo, close) ends silently; picking another tool
-/// applies it. Checked every frame and before each pointer event, so a press with a tool chosen
-/// just before it (`ui.pointer`'s `tool`) goes to that tool.
+/// or selecting another layer (Layers panel, ⌘-click, the control channel) applies it, so the box
+/// never stays on a layer that is no longer the active one (#1400). Checked every frame and before
+/// each pointer event, so a press with a tool chosen just before it (`ui.pointer`'s `tool`) goes to
+/// that tool.
 pub fn end_if_left(app: &mut PhotocraftApp) {
     let Some(t) = &app.ui.transform else { return };
-    if app.session.active().is_none_or(|st| app.transform_preview.as_ref().is_some_and(|pv| pv.doc.id != st.doc.id) || st.doc.layer(LayerId(t.layer)).is_none())
-    {
+    let Some(st) = app.session.active() else { return cancel(app) };
+    if app.transform_preview.as_ref().is_some_and(|pv| pv.doc.id != st.doc.id) || st.doc.layer(LayerId(t.layer)).is_none() {
         cancel(app);
-    } else if app.transform_preview.as_ref().is_some_and(|pv| pv.tool != app.ui.tool) {
+    } else if app.transform_preview.as_ref().is_some_and(|pv| pv.tool != app.ui.tool)
+        || (!t.selection && st.active_layer.is_some_and(|active| active.0 != t.layer))
+    {
         commit(app);
     }
 }
@@ -2075,6 +2079,56 @@ mod tests {
         assert_eq!(st.doc.layer(st.active_layer.unwrap()).unwrap().surface().unwrap().content_bounds(), photocraft_geom::Rect::new(28, 8, 44, 24));
     }
 
+    /// #1400: selecting another layer while transforming applies the box to the layer it was on,
+    /// and the next transform starts on the newly selected layer.
+    #[test]
+    fn selecting_another_layer_applies_the_transform_and_the_next_one_follows() {
+        let ctx = egui::Context::default();
+        let mut app = app_with_square(64, photocraft_geom::Rect::new(8, 8, 24, 24));
+        let first = app.session.active().unwrap().active_layer.unwrap();
+        app.run("layer.new.layer", json!({})).unwrap();
+        app.session
+            .edit("paint", |doc, a| {
+                doc.layer_mut(a.unwrap()).unwrap().surface_mut().unwrap().fill_rect(photocraft_geom::Rect::new(40, 40, 56, 60), &[0.0, 0.0, 1.0, 1.0]);
+                Ok(())
+            })
+            .unwrap();
+        let second = app.session.active().unwrap().active_layer.unwrap();
+        app.run("layer.select", json!({"layer": first.0})).unwrap();
+        app.ui.tool = Tool::Move;
+        crate::menus::invoke(&mut app, &ctx, "edit.freeTransform", json!({})).unwrap();
+        if let Some(t) = app.ui.transform.as_mut() {
+            t.quad = t.quad.map(|[x, y]| [x + 20.0, y]);
+        }
+        let steps = app.session.active().unwrap().history.past_len();
+        app.run("layer.select", json!({"layer": second.0})).unwrap();
+        end_if_left(&mut app);
+        assert!(app.ui.transform.is_none() && app.transform_preview.is_none(), "the box left the old layer");
+        let st = app.session.active().unwrap();
+        assert_eq!(st.active_layer, Some(second));
+        assert_eq!(st.history.past_len(), steps + 1, "applied as one step");
+        let bounds = |id: LayerId| st.doc.layer(id).unwrap().surface().unwrap().content_bounds();
+        assert_eq!(bounds(first), photocraft_geom::Rect::new(28, 8, 44, 24), "applied to the layer it was on");
+        assert_eq!(bounds(second), photocraft_geom::Rect::new(40, 40, 56, 60), "the new layer is untouched");
+        crate::menus::invoke(&mut app, &ctx, "edit.freeTransform", json!({})).unwrap();
+        let t = app.ui.transform.as_ref().unwrap();
+        assert_eq!((t.layer, t.rect), (second.0, [40.0, 40.0, 56.0, 60.0]), "the next box is on the selected layer");
+    }
+
+    /// Transform Selection moves the selection outline, not a layer: selecting a layer keeps it open.
+    #[test]
+    fn selecting_another_layer_keeps_a_transform_selection_open() {
+        let ctx = egui::Context::default();
+        let mut app = app_with_square(64, photocraft_geom::Rect::new(8, 8, 24, 24));
+        let first = app.session.active().unwrap().active_layer.unwrap();
+        app.run("layer.new.layer", json!({})).unwrap();
+        app.run("select.all", json!({})).unwrap();
+        begin_selection(&mut app, &ctx).unwrap();
+        app.run("layer.select", json!({"layer": first.0})).unwrap();
+        end_if_left(&mut app);
+        assert!(app.ui.transform.as_ref().is_some_and(|t| t.selection));
+    }
+
     /// A control-channel stroke that picks another tool applies the box first, then paints.
     #[test]
     fn a_pointer_request_with_another_tool_applies_the_transform_first() {