--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -7132,20 +7132,22 @@ let gPrivateBrowsingUI = {
 #ifdef XP_MACOSX
       if (!PrivateBrowsingUtils.permanentPrivateBrowsing) {
         document.documentElement.setAttribute("drawintitlebar", true);
       }
 #endif
 
       // Adjust the window's title
       let docElement = document.documentElement;
-      docElement.setAttribute("title",
-        docElement.getAttribute("title_privatebrowsing"));
-      docElement.setAttribute("titlemodifier",
-        docElement.getAttribute("titlemodifier_privatebrowsing"));
+      if (!PrivateBrowsingUtils.permanentPrivateBrowsing) {
+        docElement.setAttribute("title",
+          docElement.getAttribute("title_privatebrowsing"));
+        docElement.setAttribute("titlemodifier",
+          docElement.getAttribute("titlemodifier_privatebrowsing"));
+      }
       docElement.setAttribute("privatebrowsingmode",
         PrivateBrowsingUtils.permanentPrivateBrowsing ? "permanent" : "temporary");
       gBrowser.updateTitlebar();
 
       if (PrivateBrowsingUtils.permanentPrivateBrowsing) {
         // Adjust the New Window menu entries
         [
           { normal: "menu_newNavigator", private: "menu_newPrivateWindow" },