fix(MutationObserver): IE 11 kind of silent error: https://stackoverflow.com/questions/50593385/mutationobserver-syntax-error-on-ie-11

app/javascript/shared/stimulus-loader.ts

@@ -52,6 +52,7 @@ function lazyLoadNewControllers(application: Application) {
       }
     }
   }).observe(application.element, {
+    attributes: true,
     attributeFilter: [controllerAttribute],
     subtree: true,
     childList: true