--- a/devtools/server/actors/root.js
+++ b/devtools/server/actors/root.js
@@ -385,30 +385,31 @@ RootActor.prototype = {
 
   onListAddons: function () {
     let addonList = this._parameters.addonList;
     if (!addonList) {
       return { from: this.actorID, error: "noAddons",
                message: "This root actor has no browser addons." };
     }
 
+    // Reattach the onListChanged listener now that a client requested the list.
+    addonList.onListChanged = this._onAddonListChanged;
+
     return addonList.getList().then((addonActors) => {
       let addonActorPool = new ActorPool(this.conn);
       for (let addonActor of addonActors) {
         addonActorPool.addActor(addonActor);
       }
 
       if (this._addonActorPool) {
         this.conn.removeActorPool(this._addonActorPool);
       }
       this._addonActorPool = addonActorPool;
       this.conn.addActorPool(this._addonActorPool);
 
-      addonList.onListChanged = this._onAddonListChanged;
-
       return {
         "from": this.actorID,
         "addons": addonActors.map(addonActor => addonActor.form())
       };
     });
   },
 
   onAddonListChanged: function () {
@@ -418,28 +419,29 @@ RootActor.prototype = {
 
   onListWorkers: function () {
     let workerList = this._parameters.workerList;
     if (!workerList) {
       return { from: this.actorID, error: "noWorkers",
                message: "This root actor has no workers." };
     }
 
+    // Reattach the onListChanged listener now that a client requested the list.
+    workerList.onListChanged = this._onWorkerListChanged;
+
     return workerList.getList().then(actors => {
       let pool = new ActorPool(this.conn);
       for (let actor of actors) {
         pool.addActor(actor);
       }
 
       this.conn.removeActorPool(this._workerActorPool);
       this._workerActorPool = pool;
       this.conn.addActorPool(this._workerActorPool);
 
-      workerList.onListChanged = this._onWorkerListChanged;
-
       return {
         "from": this.actorID,
         "workers": actors.map(actor => actor.form())
       };
     });
   },
 
   onWorkerListChanged: function () {
@@ -449,28 +451,29 @@ RootActor.prototype = {
 
   onListServiceWorkerRegistrations: function () {
     let registrationList = this._parameters.serviceWorkerRegistrationList;
     if (!registrationList) {
       return { from: this.actorID, error: "noServiceWorkerRegistrations",
                message: "This root actor has no service worker registrations." };
     }
 
+    // Reattach the onListChanged listener now that a client requested the list.
+    registrationList.onListChanged = this._onServiceWorkerRegistrationListChanged;
+
     return registrationList.getList().then(actors => {
       let pool = new ActorPool(this.conn);
       for (let actor of actors) {
         pool.addActor(actor);
       }
 
       this.conn.removeActorPool(this._serviceWorkerRegistrationActorPool);
       this._serviceWorkerRegistrationActorPool = pool;
       this.conn.addActorPool(this._serviceWorkerRegistrationActorPool);
 
-      registrationList.onListChanged = this._onServiceWorkerRegistrationListChanged;
-
       return {
         "from": this.actorID,
         "registrations": actors.map(actor => actor.form())
       };
     });
   },
 
   onServiceWorkerRegistrationListChanged: function () {