--- a/devtools/server/actors/storage.js
+++ b/devtools/server/actors/storage.js
@@ -208,23 +208,23 @@ StorageActors.defaults = function(typeNa
       }
       this.onWindowReady = this.onWindowReady.bind(this);
       this.onWindowDestroyed = this.onWindowDestroyed.bind(this);
       events.on(this.storageActor, "window-ready", this.onWindowReady);
       events.on(this.storageActor, "window-destroyed", this.onWindowDestroyed);
     },
 
     destroy: function() {
-      this.hostVsStores = null;
       if (observationTopic) {
         Services.obs.removeObserver(this, observationTopic, false);
       }
       events.off(this.storageActor, "window-ready", this.onWindowReady);
       events.off(this.storageActor, "window-destroyed", this.onWindowDestroyed);
 
+      this.hostVsStores = null;
       this.storageActor = null;
     },
 
     getNamesForHost: function(host) {
       return [...this.hostVsStores.get(host).keys()];
     },
 
     getValuesForHost: function(host, name) {