diff --git a/crates/ui-egui/src/panels/viewer.rs b/crates/ui-egui/src/panels/viewer.rs
index 9adf007f..88995483 100644
--- a/crates/ui-egui/src/panels/viewer.rs
+++ b/crates/ui-egui/src/panels/viewer.rs
@@ -522,10 +522,14 @@ fn locked_pane(app: &mut EffectcraftApp, ui: &mut egui::Ui, full: Rect, bg: Colo
     let cam = (lv.view != View3D::ActiveCamera && comp.has_3d())
         .then(|| app.session.state.views3d.get(&lv.comp).cloned().unwrap_or_default().cam(lv.view, comp.width as f64, comp.height as f64).state());
     let dc = effectcraft_engine::viewer::DisplayColor::of(&app.session);
+    // The display conversion's inputs, keyed as in the main viewer's texture caches.
+    let sim = app.session.state.viewer.simulation;
+    let custom = if sim.profile == effectcraft_engine::viewer::SimProfile::MyCustom { format!("{:?}", app.session.prefs.custom_rgb) } else { String::new() };
+    let dc_key = format!("{cam:?}{}{sim:?}{}{custom}", dc.is_some(), app.session.prefs.previews.display_profile);
     let key = {
         use std::hash::{Hash, Hasher};
         let mut h = std::collections::hash_map::DefaultHasher::new();
-        (app.session.revision, lv.comp.0, t.0, scale.to_bits(), format!("{cam:?}{}", dc.is_some())).hash(&mut h);
+        (app.session.revision, lv.comp.0, t.0, scale.to_bits(), dc_key).hash(&mut h);
         h.finish()
     };
     let id = egui::Id::new("viewer-locked");
diff --git a/crates/ui-egui/tests/ui_locked_color.rs b/crates/ui-egui/tests/ui_locked_color.rs
new file mode 100644
index 00000000..d942da11
--- /dev/null
+++ b/crates/ui-egui/tests/ui_locked_color.rs
@@ -0,0 +1,81 @@
+//! The split locked viewer re-converts its pixels when the display profile or the output
+//! simulation changes (egui_kittest, texture uploads captured).
+
+use effectcraft_engine::{Session, render::RenderOpts, viewer::DisplayColor};
+use effectcraft_ui_egui::EffectcraftApp;
+use egui_kittest::{Harness, TestRenderer};
+use serde_json::{Value, json};
+use std::{cell::RefCell, collections::HashMap, rc::Rc};
+
+type Images = Rc<RefCell<HashMap<egui::TextureId, egui::ColorImage>>>;
+
+struct Capture(Images);
+
+impl TestRenderer for Capture {
+    fn handle_delta(&mut self, delta: &mut egui::TexturesDelta) {
+        for (id, ops) in std::mem::take(&mut delta.set) {
+            for op in ops {
+                let egui::ImageData::Color(image) = op.image;
+                if op.pos.is_none() && image.size[0] <= 256 && image.size[1] <= 256 {
+                    self.0.borrow_mut().insert(id, (*image).clone());
+                }
+            }
+        }
+        for id in std::mem::take(&mut delta.free) {
+            self.0.borrow_mut().remove(&id);
+        }
+    }
+
+    fn render(&mut self, _: &egui::Context, _: &egui::FullOutput) -> Result<image::RgbaImage, String> {
+        Err("Texture inspection only".into())
+    }
+}
+
+fn invoke(h: &mut Harness<'_, EffectcraftApp>, command: &str, params: Value) {
+    let ctx = h.ctx.clone();
+    effectcraft_ui_egui::menus::invoke(h.state_mut(), &ctx, command, params).unwrap();
+    h.run_steps(3);
+}
+
+fn locked_center(h: &Harness<'_, EffectcraftApp>, images: &Images) -> [u8; 4] {
+    let (_, texture) = h.ctx.data(|d| d.get_temp::<(u64, egui::TextureHandle)>(egui::Id::new("viewer-locked"))).unwrap();
+    let images = images.borrow();
+    let image = images.get(&texture.id()).unwrap();
+    image.pixels[(image.size[1] / 2) * image.size[0] + image.size[0] / 2].to_array()
+}
+
+fn expected_center(h: &mut Harness<'_, EffectcraftApp>) -> [u8; 4] {
+    let s = &mut h.state_mut().session;
+    let comp = s.active_comp_id().unwrap();
+    let image = s.render(comp, s.time(), RenderOpts::default());
+    let ci = effectcraft_ui_egui::frames::to_color_image(&image);
+    let mut pixels = vec![ci.pixels[(ci.size[1] / 2) * ci.size[0] + ci.size[0] / 2].to_array()];
+    DisplayColor::of(s).unwrap().apply(&mut pixels);
+    pixels[0]
+}
+
+#[test]
+fn locked_viewer_follows_display_profile_and_simulation() {
+    let mut s = Session::default();
+    s.execute("comp.new", json!({"name": "Color", "width": 64, "height": 64, "duration": 1})).unwrap();
+    s.execute("layer.newSolid", json!({"name": "Plate", "color": "#406080", "width": 64, "height": 64})).unwrap();
+    s.execute("file.projectSettings", json!({"workingSpace": "srgb", "outputSpace": "rec2020", "renderer": "software"})).unwrap();
+    s.execute("prefs.set", json!({"key": "previews.displayProfile", "value": "srgb"})).unwrap();
+    s.execute("view.displayColorManagement", json!({"value": true})).unwrap();
+    let images = Images::default();
+    let mut h = Harness::builder().with_size(egui::vec2(1600.0, 1000.0)).renderer(Capture(images.clone())).build_eframe(|_| EffectcraftApp::new(s));
+    h.run_steps(3);
+    invoke(&mut h, "view.splitLockedViewer", json!({}));
+    let first = expected_center(&mut h);
+    assert_eq!(locked_center(&h, &images), first);
+
+    invoke(&mut h, "prefs.set", json!({"key": "previews.displayProfile", "value": "p3"}));
+    let after_display = expected_center(&mut h);
+    assert_ne!(after_display, first);
+    assert_eq!(locked_center(&h, &images), after_display);
+
+    invoke(&mut h, "view.simulateOutput", json!({"profile": "rec709", "preserveRgb": true}));
+    let after_sim = expected_center(&mut h);
+    assert_ne!(after_sim, after_display);
+    assert_eq!(locked_center(&h, &images), after_sim);
+}