diff --git a/js/src/dom/eventHandler.js b/js/src/dom/eventHandler.js
index 95bafe4ed8cf1ad8cdcc951d0f4118f4bff610f8..17f6d077a6d3e18e82e1b3ce19217bbac009e376 100644
--- a/js/src/dom/eventHandler.js
+++ b/js/src/dom/eventHandler.js
@@ -281,7 +281,14 @@ const EventHandler = (() => {
 
       // merge custom informations in our event
       if (typeof args !== 'undefined') {
-        evt = Object.assign(evt, args)
+        Object.keys(args)
+          .forEach((key) => {
+            Object.defineProperty(evt, key, {
+              get() {
+                return args[key]
+              }
+            })
+          })
       }
 
       if (defaultPrevented) {