--- a/devtools/client/responsive.html/browser/swap.js
+++ b/devtools/client/responsive.html/browser/swap.js
@@ -1,14 +1,15 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
+const { Ci } = require("chrome");
 const promise = require("promise");
 const { Task } = require("devtools/shared/task");
 const { tunnelToInnerBrowser } = require("./tunnel");
 
 /**
  * Swap page content from an existing tab into a new browser within a container
  * page.  Page state is preserved by using `swapFrameLoaders`, just like when
  * you move a tab to a new window.  This provides a seamless transition for the
@@ -53,21 +54,26 @@ function swapToInnerBrowser({ tab, conta
 
     start: Task.async(function* () {
       tab.isResponsiveDesignMode = true;
 
       // Freeze navigation temporarily to avoid "blinking" in the location bar.
       freezeNavigationState(tab);
 
       // 1. Create a temporary, hidden tab to load the tool UI.
-      let containerTab = gBrowser.addTab(containerURL, {
+      let containerTab = gBrowser.addTab("about:blank", {
         skipAnimation: true,
+        forceNotRemote: true,
       });
       gBrowser.hideTab(containerTab);
       let containerBrowser = containerTab.linkedBrowser;
+      // Prevent the `containerURL` from ending up in the tab's history.
+      containerBrowser.loadURIWithFlags(containerURL, {
+        flags: Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_HISTORY,
+      });
 
       // Copy tab listener state flags to container tab.  Each tab gets its own tab
       // listener and state flags which cache document loading progress.  The state flags
       // are checked when switching tabs to update the browser UI.  The later step of
       // `swapBrowsersAndCloseOther` will fold the state back into the main tab.
       let stateFlags = gBrowser._tabListeners.get(tab).mStateFlags;
       gBrowser._tabListeners.get(containerTab).mStateFlags = stateFlags;
 

--- a/devtools/client/responsive.html/browser/tunnel.js
+++ b/devtools/client/responsive.html/browser/tunnel.js
@@ -2,17 +2,16 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const { Ci } = require("chrome");
 const Services = require("Services");
 const { Task } = require("devtools/shared/task");
-const DevToolsUtils = require("devtools/shared/DevToolsUtils");
 const { BrowserElementWebNavigation } = require("./web-navigation");
 const { getStack } = require("devtools/shared/platform/stack");
 
 // A symbol used to hold onto the frame loader from the outer browser while tunneling.
 const FRAME_LOADER = Symbol("devtools/responsive/frame-loader");
 
 function debug(msg) {
   // console.log(msg);
@@ -122,17 +121,18 @@ function tunnelToInnerBrowser(outer, inn
       });
 
       // The `permanentKey` property on a <xul:browser> is used to index into various maps
       // held by the session store.  When you swap content around with
       // `_swapBrowserDocShells`, these keys are also swapped so they follow the content.
       // This means the key that matches the content is on the inner browser.  Since we
       // want the browser UI to believe the page content is part of the outer browser, we
       // copy the content's `permanentKey` up to the outer browser.
-      copyPermanentKey(outer, inner);
+      debug("Copy inner permanentKey to outer browser");
+      outer.permanentKey = inner.permanentKey;
 
       // Replace the outer browser's native messageManager with a message manager tunnel
       // which we can use to route messages of interest to the inner browser instead.
       // Note: The _actual_ messageManager accessible from
       // `browser.frameLoader.messageManager` is not overridable and is left unchanged.
       // Only the XBL getter `browser.messageManager` is overridden.  Browser UI code
       // always uses this getter instead of `browser.frameLoader.messageManager` directly,
       // so this has the effect of overriding the message manager for browser UI code.
@@ -299,43 +299,16 @@ function tunnelToInnerBrowser(outer, inn
       gBrowser = null;
     },
 
   };
 }
 
 exports.tunnelToInnerBrowser = tunnelToInnerBrowser;
 
-function copyPermanentKey(outer, inner) {
-  // When we're in the process of swapping content around, we end up receiving a
-  // SessionStore:update message which lists the container page that is loaded into the
-  // outer browser (that we're hiding the inner browser within) as part of its history.
-  // We want SessionStore's view of the history for our tab to only have the page content
-  // of the inner browser, so we want to hide this message from SessionStore, but we have
-  // no direct mechanism to do so.  As a workaround, we wait until the one errant message
-  // has gone by, and then we copy the permanentKey after that, since the permanentKey is
-  // what SessionStore uses to identify each browser.
-  let outerMM = outer[FRAME_LOADER].messageManager;
-  let onHistoryEntry = message => {
-    let data = message.data.data;
-    let history = data.history || data.historychange;
-    if (!history || !history.entries) {
-      // Wait for a message that contains history data
-      return;
-    }
-    outerMM.removeMessageListener("SessionStore:update", onHistoryEntry);
-    debug("Got session update for outer browser");
-    DevToolsUtils.executeSoon(() => {
-      debug("Copy inner permanentKey to outer browser");
-      outer.permanentKey = inner.permanentKey;
-    });
-  };
-  outerMM.addMessageListener("SessionStore:update", onHistoryEntry);
-}
-
 /**
  * This module allows specific messages of interest to be directed from the
  * outer browser to the inner browser (and vice versa) in a targetted fashion
  * without having to touch the original code paths that use them.
  */
 function MessageManagerTunnel(outer, inner) {
   if (outer.isRemoteBrowser) {
     throw new Error("The outer browser must be non-remote.");