diff --git a/api/js/etemplate/et2_extension_customfields.ts b/api/js/etemplate/et2_extension_customfields.ts
index ea79542745..8009a30890 100644
--- a/api/js/etemplate/et2_extension_customfields.ts
+++ b/api/js/etemplate/et2_extension_customfields.ts
@@ -237,7 +237,7 @@ export class et2_customfields_list extends et2_valueWidget implements et2_IDetac
 						this.options.fields[field_name] = default_tab[1] !== '-private';
 					}
 				}
-				else if (this.options.customfields[field_name].tab === this.options.tab)
+				else if (this.options.tab && this.options.customfields[field_name].tab === this.options.tab)
 				{
 					this.options.fields[field_name] = true;
 				}