--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1799,8 +1799,10 @@ pref("privacy.trackingprotection.ui.enab
 #endif
 
 // Temporary pref to allow printing in e10s windows on some platforms.
 #ifdef UNIX_BUT_NOT_MAC
 pref("print.enable_e10s_testing", false);
 #else
 pref("print.enable_e10s_testing", true);
 #endif
+
+pref("browser.defaultbrowser.notificationbar", false);

--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -2280,38 +2280,33 @@ let DefaultBrowserCheck = {
       claimAllTypes = (parseFloat(version) < 6.2);
     } catch (ex) { }
 #endif
     try {
       ShellService.setDefaultBrowser(claimAllTypes, false);
     } catch (ex) {
       Cu.reportError(ex);
     }
-    this.closePrompt();
   },
 
-  _createPopup: function(win, bundle) {
+  _createPopup: function(win, notNowStrings, neverStrings) {
     let doc = win.document;
     let popup = doc.createElement("menupopup");
     popup.id = this.OPTIONPOPUP;
 
     let notNowItem = doc.createElement("menuitem");
     notNowItem.id = "defaultBrowserNotNow";
-    let label = bundle.getString("setDefaultBrowserNotNow.label");
-    notNowItem.setAttribute("label", label);
-    let accesskey = bundle.getString("setDefaultBrowserNotNow.accesskey");
-    notNowItem.setAttribute("accesskey", accesskey);
+    notNowItem.setAttribute("label", notNowStrings.label);
+    notNowItem.setAttribute("accesskey", notNowStrings.accesskey);
     popup.appendChild(notNowItem);
 
     let neverItem = doc.createElement("menuitem");
     neverItem.id = "defaultBrowserNever";
-    label = bundle.getString("setDefaultBrowserNever.label");
-    neverItem.setAttribute("label", label);
-    accesskey = bundle.getString("setDefaultBrowserNever.accesskey");
-    neverItem.setAttribute("accesskey", accesskey);
+    neverItem.setAttribute("label", neverStrings.label);
+    neverItem.setAttribute("accesskey", neverStrings.accesskey);
     popup.appendChild(neverItem);
 
     popup.addEventListener("command", this);
 
     let popupset = doc.getElementById("mainPopupSet");
     popupset.appendChild(popup);
   },
 
@@ -2327,50 +2322,82 @@ let DefaultBrowserCheck = {
   prompt: function(win) {
     let brandBundle = win.document.getElementById("bundle_brand");
     let shellBundle = win.document.getElementById("bundle_shell");
 
     let brandShortName = brandBundle.getString("brandShortName");
     let promptMessage = shellBundle.getFormattedString("setDefaultBrowserMessage2",
                                                        [brandShortName]);
 
-    let confirmMessage = shellBundle.getFormattedString("setDefaultBrowserConfirm.label",
-                                                        [brandShortName]);
-    let confirmKey = shellBundle.getString("setDefaultBrowserConfirm.accesskey");
+    let yesButton = shellBundle.getFormattedString("setDefaultBrowserConfirm.label",
+                                                   [brandShortName]);
+
+    let notNowButton = shellBundle.getString("setDefaultBrowserNotNow.label");
+    let notNowButtonKey = shellBundle.getString("setDefaultBrowserNotNow.accesskey");
+
+    let neverLabel = shellBundle.getString("setDefaultBrowserNever.label");
+    let neverKey = shellBundle.getString("setDefaultBrowserNever.accesskey");
 
-    let optionsMessage = shellBundle.getString("setDefaultBrowserOptions.label");
-    let optionsKey = shellBundle.getString("setDefaultBrowserOptions.accesskey");
+    let useNotificationBar = Services.prefs.getBoolPref("browser.defaultbrowser.notificationbar");
+    if (useNotificationBar) {
+      let optionsMessage = shellBundle.getString("setDefaultBrowserOptions.label");
+      let optionsKey = shellBundle.getString("setDefaultBrowserOptions.accesskey");
+
+      let yesButtonKey = shellBundle.getString("setDefaultBrowserConfirm.accesskey");
 
-    let selectedBrowser = win.gBrowser.selectedBrowser;
-    let notificationBox = win.document.getElementById("high-priority-global-notificationbox");
+      let notificationBox = win.document.getElementById("high-priority-global-notificationbox");
 
-    this._createPopup(win, shellBundle);
+      this._createPopup(win, {
+        label: notNowButton,
+        accesskey: notNowButtonKey
+      }, {
+        label: neverLabel,
+        accesskey: neverKey
+      });
 
-    let buttons = [
-      {
-        label: confirmMessage,
-        accessKey: confirmKey,
-        callback: this.setAsDefault.bind(this)
-      },
-      {
-        label: optionsMessage,
-        accessKey: optionsKey,
-        popup: this.OPTIONPOPUP
+      let buttons = [
+        {
+          label: yesButton,
+          accessKey: yesButtonKey,
+          callback: () => {
+            this.setAsDefault();
+            this.closePrompt();
+          }
+        },
+        {
+          label: optionsMessage,
+          accessKey: optionsKey,
+          popup: this.OPTIONPOPUP
+        }
+      ];
+
+      let iconPixels = win.devicePixelRatio > 1 ? "32" : "16";
+      let iconURL = "chrome://branding/content/icon" + iconPixels + ".png";
+      const priority = notificationBox.PRIORITY_WARNING_HIGH;
+      let callback = this._onNotificationEvent.bind(this);
+      this._notification = notificationBox.appendNotification(promptMessage, "default-browser",
+                                                              iconURL, priority, buttons,
+                                                              callback);
+    } else {
+      // Modal prompt
+      let promptTitle = shellBundle.getString("setDefaultBrowserTitle");
+
+      let ps = Services.prompt;
+      let dontAsk = { value: false };
+      let buttonFlags = (ps.BUTTON_TITLE_IS_STRING * ps.BUTTON_POS_0) +
+                        (ps.BUTTON_TITLE_IS_STRING * ps.BUTTON_POS_1) +
+                        ps.BUTTON_POS_0_DEFAULT;
+      let rv = ps.confirmEx(win, promptTitle, promptMessage, buttonFlags,
+                            yesButton, notNowButton, null, neverLabel, dontAsk);
+      if (rv == 0) {
+        this.setAsDefault();
+      } else if (dontAsk.value) {
+        ShellService.shouldCheckDefaultBrowser = false;
       }
-    ];
-
-
-    let iconPixels = win.devicePixelRatio > 1 ? "32" : "16";
-    let iconURL = "chrome://branding/content/icon" + iconPixels + ".png";
-    const priority = notificationBox.PRIORITY_WARNING_HIGH;
-    let callback = this._onNotificationEvent.bind(this);
-    this._notification = notificationBox.appendNotification(promptMessage, "default-browser",
-                                                            iconURL, priority, buttons,
-                                                            callback);
-    this._notification.persistence = -1;
+    }
   },
 
   _onNotificationEvent: function(eventType) {
     if (eventType == "removed") {
       let doc = this._notification.ownerDocument;
       let popup = doc.getElementById(this.OPTIONPOPUP);
       popup.removeEventListener("command", this);
       popup.remove();