--- a/toolkit/components/extensions/ext-notifications.js
+++ b/toolkit/components/extensions/ext-notifications.js
@@ -49,29 +49,32 @@ Notification.prototype = {
       // This will fail if the OS doesn't support this function.
     }
     notificationsMap.get(this.extension).delete(this.id);
   },
 
   observe(subject, topic, data) {
     let notifications = notificationsMap.get(this.extension);
 
+    function emitAndDelete(event) {
+      notifications.emit(event, data);
+      notifications.delete(this.id);
+    }
+
     // Don't try to emit events if the extension has been unloaded
     if (!notifications) {
       return;
     }
 
     if (topic === "alertclickcallback") {
-      notifications.emit("clicked", data);
+      emitAndDelete("clicked");
     }
     if (topic === "alertfinished") {
-      notifications.emit("closed", data);
+      emitAndDelete("closed");
     }
-
-    notifications.delete(this.id);
   },
 };
 
 /* eslint-disable mozilla/balanced-listeners */
 extensions.on("startup", (type, extension) => {
   let map = new Map();
   EventEmitter.decorate(map);
   notificationsMap.set(extension, map);