diff --git a/crates/ui-egui/src/control.rs b/crates/ui-egui/src/control.rs
index 480824d0..7cc94b51 100644
--- a/crates/ui-egui/src/control.rs
+++ b/crates/ui-egui/src/control.rs
@@ -427,7 +427,14 @@ pub fn handle(app: &mut FigApp, ctx: &Context, method: &str, p: &Value) -> Resul
             // Comment thread popover: an id opens it, null closes it.
             if let Some(v) = p.get("commentOpen") {
                 match v.as_u64() {
-                    Some(id) => app.ui.comments.show(id),
+                    Some(id) => {
+                        // Pins are drawn for the current page only: reveal the thread's page first.
+                        let page = app.session.doc().ok().and_then(|d| d.comment(id)).map(|c| c.page);
+                        if let Some(page) = page.filter(|p| app.session.page().is_ok_and(|cur| cur != *p)) {
+                            app.session.execute("page.select", &json!({"id": page.0})).map_err(|e| e.to_string())?;
+                        }
+                        app.ui.comments.show(id);
+                    }
                     None => app.ui.comments.close(),
                 }
             }
diff --git a/crates/ui-egui/tests/comment_open_other_page.rs b/crates/ui-egui/tests/comment_open_other_page.rs
new file mode 100644
index 00000000..1036c604
--- /dev/null
+++ b/crates/ui-egui/tests/comment_open_other_page.rs
@@ -0,0 +1,41 @@
+use egui::{Pos2, RawInput, Rect, vec2};
+use figcraft_engine::Session;
+use figcraft_ui_egui::{FigApp, NoServices, control};
+use serde_json::json;
+
+fn frame(ctx: &egui::Context, app: &mut FigApp, time: f64) {
+    let mut out = ctx
+        .run_ui(RawInput { screen_rect: Some(Rect::from_min_size(Pos2::ZERO, vec2(1440.0, 900.0))), time: Some(time), ..Default::default() }, |ui| {
+            app.ui(ui)
+        });
+    out.textures_delta.clear();
+}
+
+#[test]
+fn comment_open_other_page() {
+    let mut session = Session::new();
+    let first = session.page().unwrap();
+    let second = session.execute("page.add", &json!({})).unwrap()["id"].as_u64().unwrap();
+    session.execute("page.select", &json!({"id": second})).unwrap();
+    let comment = session.execute("comment.add", &json!({"x": 50, "y": 50, "text": "Review this"})).unwrap()["id"].as_u64().unwrap();
+    let ctx = egui::Context::default();
+    let mut app = FigApp::new(session, Box::new(NoServices));
+    for i in 1..=3 {
+        frame(&ctx, &mut app, i as f64 / 60.0);
+    }
+    // Same page: stays open.
+    control::handle(&mut app, &ctx, "ui.set", &json!({"commentOpen": comment})).unwrap();
+    frame(&ctx, &mut app, 4.0 / 60.0);
+    assert_eq!(app.inspect()["comments"]["open"], json!(comment));
+    // null closes it.
+    control::handle(&mut app, &ctx, "ui.set", &json!({"commentOpen": null})).unwrap();
+    frame(&ctx, &mut app, 5.0 / 60.0);
+    assert_eq!(app.inspect()["comments"]["open"], json!(null));
+    // Another page: the page is revealed and the thread stays open across a frame.
+    control::handle(&mut app, &ctx, "engine.execute", &json!({"command": "page.select", "params": {"id": first}})).unwrap();
+    let reply = control::handle(&mut app, &ctx, "ui.set", &json!({"commentOpen": comment})).unwrap();
+    assert_eq!(reply["comments"]["open"], json!(comment));
+    frame(&ctx, &mut app, 6.0 / 60.0);
+    assert_eq!(app.session.page().unwrap().0, second);
+    assert_eq!(app.inspect()["comments"]["open"], json!(comment), "ui.set should keep the requested popover open across a frame");
+}