--- a/devtools/client/framework/test/browser_devtools_api.js
+++ b/devtools/client/framework/test/browser_devtools_api.js
@@ -1,24 +1,26 @@
 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set ft=javascript ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 // Tests devtools API
 
+"use strict";
+
 const toolId1 = "test-tool-1";
 const toolId2 = "test-tool-2";
 
 function test() {
   addTab("about:blank").then(runTests1);
 }
 
 // Test scenario 1: the tool definition build method returns a promise.
-function runTests1(aTab) {
+function runTests1(tab) {
   let toolDefinition = {
     id: toolId1,
     isTargetSupported: () => true,
     visibilityswitch: "devtools.test-tool.enabled",
     url: "about:blank",
     label: "someLabel",
     build: function (iframeWindow, toolbox) {
       let panel = createTestPanel(iframeWindow, toolbox);
@@ -37,37 +39,37 @@ function runTests1(aTab) {
   let target = TargetFactory.forTab(gBrowser.selectedTab);
 
   let events = {};
 
   // Check events on the gDevTools and toolbox objects.
   gDevTools.once(toolId1 + "-init", (event, toolbox, iframe) => {
     ok(iframe, "iframe argument available");
 
-    toolbox.once(toolId1 + "-init", (event, iframe) => {
-      ok(iframe, "iframe argument available");
-      events["init"] = true;
+    toolbox.once(toolId1 + "-init", (innerEvent, innerIframe) => {
+      ok(innerIframe, "innerIframe argument available");
+      events.init = true;
     });
   });
 
   gDevTools.once(toolId1 + "-ready", (event, toolbox, panel) => {
     ok(panel, "panel argument available");
 
-    toolbox.once(toolId1 + "-ready", (event, panel) => {
-      ok(panel, "panel argument available");
-      events["ready"] = true;
+    toolbox.once(toolId1 + "-ready", (innerEvent, innerPanel) => {
+      ok(innerPanel, "innerPanel argument available");
+      events.ready = true;
     });
   });
 
   gDevTools.showToolbox(target, toolId1).then(function (toolbox) {
     is(toolbox.target, target, "toolbox target is correct");
     is(toolbox.target.tab, gBrowser.selectedTab, "targeted tab is correct");
 
-    ok(events["init"], "init event fired");
-    ok(events["ready"], "ready event fired");
+    ok(events.init, "init event fired");
+    ok(events.ready, "ready event fired");
 
     gDevTools.unregisterTool(toolId1);
 
     // Wait for unregisterTool to select the next tool before calling runTests2,
     // otherwise we will receive the wrong select event when waiting for
     // unregisterTool to select the next tool in continueTests below.
     toolbox.once("select", runTests2);
   });
@@ -96,47 +98,47 @@ function runTests2() {
   let target = TargetFactory.forTab(gBrowser.selectedTab);
 
   let events = {};
 
   // Check events on the gDevTools and toolbox objects.
   gDevTools.once(toolId2 + "-init", (event, toolbox, iframe) => {
     ok(iframe, "iframe argument available");
 
-    toolbox.once(toolId2 + "-init", (event, iframe) => {
-      ok(iframe, "iframe argument available");
-      events["init"] = true;
+    toolbox.once(toolId2 + "-init", (innerEvent, innerIframe) => {
+      ok(innerIframe, "innerIframe argument available");
+      events.init = true;
     });
   });
 
   gDevTools.once(toolId2 + "-build", (event, toolbox, panel, iframe) => {
     ok(panel, "panel argument available");
 
-    toolbox.once(toolId2 + "-build", (event, panel, iframe) => {
-      ok(panel, "panel argument available");
-      events["build"] = true;
+    toolbox.once(toolId2 + "-build", (innerEvent, innerPanel, innerIframe) => {
+      ok(innerPanel, "innerPanel argument available");
+      events.build = true;
     });
   });
 
   gDevTools.once(toolId2 + "-ready", (event, toolbox, panel) => {
     ok(panel, "panel argument available");
 
-    toolbox.once(toolId2 + "-ready", (event, panel) => {
-      ok(panel, "panel argument available");
-      events["ready"] = true;
+    toolbox.once(toolId2 + "-ready", (innerEvent, innerPanel) => {
+      ok(innerPanel, "innerPanel argument available");
+      events.ready = true;
     });
   });
 
   gDevTools.showToolbox(target, toolId2).then(function (toolbox) {
     is(toolbox.target, target, "toolbox target is correct");
     is(toolbox.target.tab, gBrowser.selectedTab, "targeted tab is correct");
 
-    ok(events["init"], "init event fired");
-    ok(events["build"], "build event fired");
-    ok(events["ready"], "ready event fired");
+    ok(events.init, "init event fired");
+    ok(events.build, "build event fired");
+    ok(events.ready, "ready event fired");
 
     continueTests(toolbox);
   });
 }
 
 var continueTests = Task.async(function* (toolbox, panel) {
   ok(toolbox.getCurrentPanel(), "panel value is correct");
   is(toolbox.currentToolId, toolId2, "toolbox _currentToolId is correct");
@@ -179,16 +181,17 @@ var continueTests = Task.async(function*
   ok(toolbox.isToolRegistered(toolId2),
     "Toolbox: The tool is registered");
   ok(gDevTools.getToolDefinitionMap().has(toolId2),
     "The tool is registered");
 
   info("Unregistering tool");
   gDevTools.unregisterTool(toolId2);
 
+  info("Destroying toolbox");
   destroyToolbox(toolbox);
 });
 
 function destroyToolbox(toolbox) {
   toolbox.destroy().then(function () {
     let target = TargetFactory.forTab(gBrowser.selectedTab);
     ok(gDevTools._toolboxes.get(target) == null, "gDevTools doesn't know about target");
     ok(toolbox.target == null, "toolbox doesn't know about target.");

--- a/devtools/client/storage/ui.js
+++ b/devtools/client/storage/ui.js
@@ -137,17 +137,26 @@ function StorageUI(front, target, panelW
   let key = L10N.getStr("storage.filter.key");
   shortcuts.on(key, (name, event) => {
     event.preventDefault();
     this.searchBox.focus();
   });
 
   this.front.listStores().then(storageTypes => {
     this.populateStorageTree(storageTypes);
-  }).then(null, console.error);
+  }).catch(e => {
+    if (!this._toolbox || this._toolbox._destroyer) {
+      // The toolbox is in the process of being destroyed... in this case throwing here
+      // is expected and normal so let's ignore the error.
+      return;
+    }
+
+    // The toolbox is open so the error is unexpected and real so let's log it.
+    console.error(e);
+  });
 
   this.onUpdate = this.onUpdate.bind(this);
   this.front.on("stores-update", this.onUpdate);
   this.onCleared = this.onCleared.bind(this);
   this.front.on("stores-cleared", this.onCleared);
 
   this.handleKeypress = this.handleKeypress.bind(this);
   this._panelDoc.addEventListener("keypress", this.handleKeypress);