diff --git a/src/Umbraco.Web.UI.Client/src/packages/core/content-type/workspace/views/design/content-type-design-editor-tab.element.ts b/src/Umbraco.Web.UI.Client/src/packages/core/content-type/workspace/views/design/content-type-design-editor-tab.element.ts
index 811ea1e1c9..ff3c999434 100644
--- a/src/Umbraco.Web.UI.Client/src/packages/core/content-type/workspace/views/design/content-type-design-editor-tab.element.ts
+++ b/src/Umbraco.Web.UI.Client/src/packages/core/content-type/workspace/views/design/content-type-design-editor-tab.element.ts
@@ -187,7 +187,7 @@ export class UmbContentTypeDesignEditorTabElement extends UmbLitElement {
 				<div class="container-list" ?sort-mode-active=${this._sortModeActive}>
 					${repeat(
 						this._groups,
-						(group) => group.id + '_' + group.name + '_' + group.parent?.id ?? '',
+						(group) => group.id + '_' + group.name + '_' + (group.parent?.id ?? ''),
 						(group) => html`
 							<b>${group.id}</b>
 							<umb-content-type-design-editor-group