diff --git a/dom/notification/Notification.cpp b/dom/notification/Notification.cpp
index c77e3ba7eb84..65530a38bb35 100644
--- a/dom/notification/Notification.cpp
+++ b/dom/notification/Notification.cpp
@@ -1317,6 +1317,8 @@ bool Notification::IsInPrivateBrowsing() {
   return false;
 }
 
+// Step 4 of
+// https://notifications.spec.whatwg.org/#dom-notification-notification
 void Notification::ShowInternal() {
   AssertIsOnMainThread();
   MOZ_ASSERT(mTempRef,
@@ -1331,13 +1333,15 @@ void Notification::ShowInternal() {
   std::swap(ownership, mTempRef);
   MOZ_ASSERT(ownership->GetNotification() == this);
 
-  nsresult rv = PersistNotification();
-  if (NS_FAILED(rv)) {
-    NS_WARNING("Could not persist Notification");
-  }
-
   nsCOMPtr<nsIAlertsService> alertService = components::Alerts::Service();
 
+  // Step 4.1: If the result of getting the notifications permission state is
+  // not "granted", then queue a task to fire an event named error on this, and
+  // abort these steps.
+  //
+  // XXX(krosylight): But this function is also triggered by
+  // Notification::ShowPersistentNotification which already does its own
+  // permission check. Can we split this?
   ErrorResult result;
   NotificationPermission permission = NotificationPermission::Denied;
   if (mWorkerPrivate) {
@@ -1358,13 +1362,28 @@ void Notification::ShowInternal() {
     } else {
       DispatchTrustedEvent(u"error"_ns);
     }
+    mIsClosed = true;
     return;
   }
 
+  // Preparing for Step 4.2 the fetch steps. The actual work happens in
+  // nsIAlertNotification::LoadImage
   nsAutoString iconUrl;
   nsAutoString soundUrl;
   ResolveIconAndSoundURL(iconUrl, soundUrl);
 
+  // Step 4.3 the show steps, which are almost all about processing `tag` and
+  // then displaying the notification. Both are handled by
+  // nsIAlertsService::ShowAlert/PersistentNotification. The below is all about
+  // constructing the observer (for show and close events) right and ultimately
+  // call the alerts service function.
+
+  // XXX(krosylight): Non-persistent notifications probably don't need this
+  nsresult rv = PersistNotification();
+  if (NS_FAILED(rv)) {
+    NS_WARNING("Could not persist Notification");
+  }
+
   bool isPersistent = false;
   nsCOMPtr<nsIObserver> observer;
   if (mScope.IsEmpty()) {
diff --git a/widget/windows/ToastNotification.cpp b/widget/windows/ToastNotification.cpp
index afdffc19acbe..83692b26a18f 100644
--- a/widget/windows/ToastNotification.cpp
+++ b/widget/windows/ToastNotification.cpp
@@ -776,6 +776,9 @@ ToastNotification::CloseAlert(const nsAString& aAlertName,
                               bool aContextClosed) {
   RefPtr<ToastNotificationHandler> handler;
   if (NS_WARN_IF(!mActiveHandlers.Get(aAlertName, getter_AddRefs(handler)))) {
+    // This can happen when the handler is gone but the closure signal is not
+    // yet reached to the content process, and then the process tries closing
+    // the same signal.
     return NS_OK;
   }