diff --git a/packages/core/package.json b/packages/core/package.json
index e637eecc..ef6cc752 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@thatopen/components",
   "description": "Collection of core functionalities to author BIM apps.",
-  "version": "2.1.9",
+  "version": "2.1.11",
   "author": "That Open Company",
   "contributors": [
     "Antonio Gonzalez Viegas (https://github.com/agviegas)",
diff --git a/packages/core/src/core/Components/index.ts b/packages/core/src/core/Components/index.ts
index 5dd2a827..79a41adb 100644
--- a/packages/core/src/core/Components/index.ts
+++ b/packages/core/src/core/Components/index.ts
@@ -14,7 +14,7 @@ export class Components implements Disposable {
   /**
    * The version of the @thatopen/components library.
    */
-  static readonly release = "2.1.9";
+  static readonly release = "2.1.11";
 
   /** {@link Disposable.onDisposed} */
   readonly onDisposed = new Event<void>();
diff --git a/packages/core/src/fragments/Classifier/index.ts b/packages/core/src/fragments/Classifier/index.ts
index e075add0..237b62e9 100644
--- a/packages/core/src/fragments/Classifier/index.ts
+++ b/packages/core/src/fragments/Classifier/index.ts
@@ -356,7 +356,7 @@ export class Classifier extends Component implements Disposable {
    */
   async bySpatialStructure(
     model: FRAGS.FragmentsGroup,
-    config: { useProperties?: boolean; isolate?: Set<number> },
+    config: { useProperties?: boolean; isolate?: Set<number> } = {},
   ) {
     const indexer = this.components.get(IfcRelationsIndexer);
     const modelRelations = indexer.relationMaps[model.uuid];
@@ -368,8 +368,8 @@ export class Classifier extends Component implements Disposable {
     const systemName = "spatialStructures";
 
     // If useProperties is undefined, use properties by default
-    const propsUndefined = config.useProperties === undefined;
-    const useProperties = propsUndefined || config.useProperties;
+    const noProps = config.useProperties === undefined;
+    const useProperties = noProps || config.useProperties;
 
     for (const [expressID] of modelRelations) {
       // E.g. if the user just wants the building storeys
diff --git a/packages/core/src/fragments/Hider/example.ts b/packages/core/src/fragments/Hider/example.ts
index c1c5ce4b..2d09d6e7 100644
--- a/packages/core/src/fragments/Hider/example.ts
+++ b/packages/core/src/fragments/Hider/example.ts
@@ -20,6 +20,7 @@ In this tutorial, we will import:
 
 import Stats from "stats.js";
 import * as BUI from "@thatopen/ui";
+import * as WEBIFC from "web-ifc";
 import * as OBC from "@thatopen/components";
 
 /* MD
@@ -109,7 +110,9 @@ const hider = components.get(OBC.Hider);
 
 const classifier = components.get(OBC.Classifier);
 classifier.byEntity(model);
-await classifier.bySpatialStructure(model);
+await classifier.bySpatialStructure(model, {
+  isolate: new Set([WEBIFC.IFCBUILDINGSTOREY]),
+});
 
 /* MD
   ### ⏱️ Measuring the performance (optional)
diff --git a/packages/core/src/ifc/IfcRelationsIndexer/index.ts b/packages/core/src/ifc/IfcRelationsIndexer/index.ts
index 2a46a629..761fa013 100644
--- a/packages/core/src/ifc/IfcRelationsIndexer/index.ts
+++ b/packages/core/src/ifc/IfcRelationsIndexer/index.ts
@@ -259,7 +259,7 @@ export class IfcRelationsIndexer extends Component implements Disposable {
     }
     const entityRelations = indexMap.get(expressID);
     const attributeIndex = this.getAttributeIndex(relationName);
-    if (!(entityRelations && attributeIndex)) {
+    if (entityRelations === undefined || attributeIndex === null) {
       return null;
     }
     const relations = entityRelations.get(attributeIndex);