diff --git a/ts_web/elements/wcc-properties.ts b/ts_web/elements/wcc-properties.ts
index a3547f8..e4f5dd0 100644
--- a/ts_web/elements/wcc-properties.ts
+++ b/ts_web/elements/wcc-properties.ts
@@ -268,6 +268,9 @@ export class WccProperties extends LitElement {
         }
       }
       const classProperties: Map<string, any> = anonItem.elementProperties;
+      if (!classProperties) {
+        return;
+      }
       const propertyArray: TemplateResult[] = [];
       for (const key of classProperties.keys()) {
         if (key === 'goBright' || key === 'domtools') {