diff --git a/docs/requirements.md b/docs/requirements.md
index 3b094aa65..0cb04646b 100644
--- a/docs/requirements.md
+++ b/docs/requirements.md
@@ -819,6 +819,7 @@ Internal architecture, components, and application logic.
 | UT-246 | Opening a PiP window disarms background audio, and a background signal arriving with the native PiP flag false is still treated as PiP while the frontend's latch says the window is open — without resurrecting one it has already seen close | DR-266 | Done |
 | UT-247 | A library whose `collection_type` has no mapping — Books, Photos, a mixed library — does not return the server's films, albums and shows from cache | DR-277 | Done |
 | UT-248 | Narrowing the library clause does not starve the libraries that do have landing pages: music, movies and TV each still list their own media and none of the others | DR-277 | Done |
+| UT-249 | Opening an individual collection still lists its own children: a BoxSet's members are matched by the stored `parent_id`, not by the library clause, so narrowing that clause did not empty collections | DR-277 | Done |
 ### Integration Tests
 
 | Test ID | Test Description | Traces To | Status |
diff --git a/src-tauri/src/repository/offline.rs b/src-tauri/src/repository/offline.rs
index 037754217..e493dd171 100644
--- a/src-tauri/src/repository/offline.rs
+++ b/src-tauri/src/repository/offline.rs
@@ -5037,15 +5037,67 @@ mod tests {
     #[tokio::test]
     async fn test_get_items_unknown_library_type_does_not_return_whole_server() {
         let db = create_test_db();
-        seed_library(&db, "books-lib", "books").await;
 
         insert_item(&db, "movie-1", "Movie", None, None, None).await;
         insert_item(&db, "album-1", "MusicAlbum", None, None, None).await;
         insert_item(&db, "series-1", "Series", None, None, None).await;
 
+        // Every library kind the app has no landing page for, including the
+        // empty `collection_type` Jellyfin sends for a mixed library.
+        for collection_type in ["books", "boxsets", "photos", "homevideos", ""] {
+            let lib = format!("lib-{collection_type}");
+            seed_library(&db, &lib, collection_type).await;
+
+            let repo = make_repo(&db);
+            let ids: Vec<String> = repo
+                .get_items(&lib, None)
+                .await
+                .unwrap()
+                .items
+                .iter()
+                .map(|i| i.id.clone())
+                .collect();
+
+            assert!(
+                ids.is_empty(),
+                "a '{collection_type}' library must not serve the server's films, \
+                 albums and shows; got {:?}",
+                ids
+            );
+        }
+    }
+
+    /// Opening an individual collection is a different path and must keep
+    /// working: a BoxSet's children carry `parent_id`, which the cache does
+    /// store, so they are matched by the ordinary parent link rather than by
+    /// the library clause this fix narrowed.
+    ///
+    /// Worth pinning separately — narrowing the library clause could plausibly
+    /// have taken collections with it, and "Collections is empty" would look
+    /// identical to the bug it was meant to fix.
+    ///
+    /// TRACES: UR-007 | DR-277 | UT-249
+    #[tokio::test]
+    async fn test_get_items_collection_lists_its_own_children() {
+        let db = create_test_db();
+        seed_library(&db, "boxset-lib", "boxsets").await;
+
+        insert_item(&db, "boxset-1", "BoxSet", None, None, None).await;
+        insert_item(&db, "outsider", "Movie", None, None, None).await;
+
+        // A film inside the collection: linked by parent_id, which is what a
+        // BoxSet's children actually carry.
+        db.execute(Query::with_params(
+            "INSERT INTO items (id, server_id, name, item_type, parent_id, synced_at) \
+             VALUES ('in-set', 'test-server', 'In The Set', 'Movie', ?1, '2024-01-01')",
+            vec![QueryParam::String("boxset-1".to_string())],
+        ))
+        .await
+        .unwrap();
+
         let repo = make_repo(&db);
         let ids: Vec<String> = repo
-            .get_items("books-lib", None)
+            .get_items("boxset-1", None)
             .await
             .unwrap()
             .items
@@ -5053,11 +5105,10 @@ mod tests {
             .map(|i| i.id.clone())
             .collect();
 
-        assert!(
-            !ids.contains(&"movie-1".to_string())
-                && !ids.contains(&"album-1".to_string())
-                && !ids.contains(&"series-1".to_string()),
-            "a Books library must not serve the server's films, albums and shows; got {:?}",
+        assert_eq!(
+            ids,
+            vec!["in-set".to_string()],
+            "a collection lists its own children and nothing else; got {:?}",
             ids
         );
     }