diff --git a/js/src/forum/utils/KeyboardNavigatable.ts b/js/src/forum/utils/KeyboardNavigatable.ts
index 1e9dc5568..739a590fc 100644
--- a/js/src/forum/utils/KeyboardNavigatable.ts
+++ b/js/src/forum/utils/KeyboardNavigatable.ts
@@ -104,7 +104,9 @@ export default class KeyboardNavigatable {
    * Provide a callback that determines whether keyboard input should be handled.
    */
   when(callback: ShouldHandle): KeyboardNavigatable {
-    return { ...this, whenCallback: callback };
+    this.whenCallback = callback;
+
+    return this;
   }
 
   /**