--- a/browser/devtools/framework/toolbox.js
+++ b/browser/devtools/framework/toolbox.js
@@ -263,17 +263,17 @@ Toolbox.prototype = {
     let deferred = promise.defer();
 
     return this._host.create().then(iframe => {
       let deferred = promise.defer();
 
       let domReady = () => {
         this.isReady = true;
 
-        this._listFrames();
+        let framesPromise = this._listFrames();
 
         this.closeButton = this.doc.getElementById("toolbox-close");
         this.closeButton.addEventListener("command", this.destroy, true);
 
         gDevTools.on("pref-changed", this._prefChanged);
 
         let framesMenu = this.doc.getElementById("command-button-frames");
         framesMenu.addEventListener("command", this.selectFrame, true);
@@ -304,17 +304,18 @@ Toolbox.prototype = {
           // console input will receive focus.
           let splitConsolePromise = promise.resolve();
           if (Services.prefs.getBoolPref(SPLITCONSOLE_ENABLED_PREF)) {
             splitConsolePromise = this.openSplitConsole();
           }
 
           promise.all([
             splitConsolePromise,
-            buttonsPromise
+            buttonsPromise,
+            framesPromise
           ]).then(() => {
             this.emit("ready");
             deferred.resolve();
           }, deferred.reject);
         });
       };
 
       // Load the toolbox-level actor fronts and utilities now
@@ -1224,23 +1225,23 @@ Toolbox.prototype = {
                                toolName, this.target.url || this.target.name);
     this._host.setTitle(title);
   },
 
   _listFrames: function (event) {
     if (!this._target.form || !this._target.form.actor) {
       // We are not targetting a regular TabActor
       // it can be either an addon or browser toolbox actor
-      return;
+      return promise.resolve();
     }
     let packet = {
       to: this._target.form.actor,
       type: "listFrames"
     };
-    this._target.client.request(packet, resp => {
+    return this._target.client.request(packet, resp => {
       this._updateFrames(null, { frames: resp.frames });
     });
   },
 
   selectFrame: function (event) {
     let windowId = event.target.getAttribute("data-window-id");
     let packet = {
       to: this._target.form.actor,