diff --git a/application/source/dom/customelement.mjs b/application/source/dom/customelement.mjs
index 94c93044b14d150e73554c21b6ee35465733f702..7e7d86f88dacb36367f26313187e6991205feccd 100644
--- a/application/source/dom/customelement.mjs
+++ b/application/source/dom/customelement.mjs
@@ -198,11 +198,11 @@ class CustomElement extends HTMLElement {
      */
     constructor() {
         super();
-        
+
+        this[attributeObserverSymbol] = {};
         this[internalSymbol] = new ProxyObserver({
             options: initOptionsFromAttributes(this, extend({}, this.defaults)),
         });
-        this[attributeObserverSymbol] = {};
         initOptionObserver.call(this);
         this[initMethodSymbol]();
     }