diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index 2d882e4b..68407b8f 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -1420,7 +1420,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                             document.title = document.title.replace(RegExp("(.*)" + util.regexp.escape(old)), "$1" + current);
                     }
 
-                    if (services.has("privateBrowsing")) {
+                    if (win.hasAttribute("titlemodifier_privatebrowsing")) {
                         let oldValue = win.getAttribute("titlemodifier_normal");
                         let suffix = win.getAttribute("titlemodifier_privatebrowsing").substr(oldValue.length);
 
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index f2a7af36..88c4215d 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -133,7 +133,7 @@ function require_(obj, name, from, targetName) {
 defineModule("base", {
     // sed -n 's/^(const|var|function) ([a-zA-Z0-9_]+).*/	"\2",/p' base.jsm | sort | fmt
     exports: [
-        "ErrorBase", "Cc", "Ci", "Class", "Cr", "Cu", "Module", "JSMLoader",
+        "ErrorBase", "Cc", "Ci", "Class", "Cr", "Cu", "Finished", "Module", "JSMLoader",
         "Set", "Struct", "StructBase", "Timer", "UTF8", "XPCOM", "XPCOMShim", "XPCOMUtils",
         "XPCSafeJSObjectWrapper", "array", "bind", "call", "callable", "ctypes", "curry",
         "debuggerProperties", "defineModule", "deprecated", "endModule", "forEach", "isArray",
@@ -1110,6 +1110,12 @@ var ErrorBase = Class("ErrorBase", Error, {
     toString: function () String(this.message)
 });
 
+/**
+ * An Error subclass to throw in order to stop sourcing a plugin without
+ * printing a stack trace.
+ */
+var Finished = Class("Finished", ErrorBase);
+
 /**
  * Constructs a new Module class and instantiates an instance into the current
  * module global object.
diff --git a/common/modules/io.jsm b/common/modules/io.jsm
index 9eb6d2ba..9e717d74 100644
--- a/common/modules/io.jsm
+++ b/common/modules/io.jsm
@@ -151,7 +151,7 @@ var IO = Module("io", {
                         dactyl.triggerObserver("io.source", context, file, file.lastModifiedTime);
                     }
 
-                    if (/\.js,$/.test(filename))
+                    if (/\.jsm$/.test(filename))
                         sourceJSM();
                     else if (/\.js$/.test(filename)) {
                         try {
@@ -168,6 +168,8 @@ var IO = Module("io", {
                                 sourceJSM();
                             }
                             else {
+                                if (e instanceof Finished)
+                                    return;
                                 if (e.fileName && !(e instanceof FailedAssertion))
                                     try {
                                         e.fileName = util.fixURI(e.fileName);
diff --git a/common/modules/sanitizer.jsm b/common/modules/sanitizer.jsm
index a928fff1..9b4eb547 100644
--- a/common/modules/sanitizer.jsm
+++ b/common/modules/sanitizer.jsm
@@ -121,12 +121,16 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
             },
             override: true
         });
-        if (services.has("privateBrowsing"))
+        try {
+            var { ForgetAboutSite } = Cu.import("resource://gre/modules/ForgetAboutSite.jsm", {});
+        }
+        catch (e) {}
+        if (ForgetAboutSite)
             this.addItem("host", {
                 description: "All data from the given host",
                 action: function (range, host) {
                     if (host)
-                        services.privateBrowsing.removeDataFromDomain(host);
+                        ForgetAboutSite.removeDataFromDomain(host);
                 }
             });
         this.addItem("sitesettings", {
@@ -595,7 +599,7 @@ var Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakRef
     },
     options: function initOptions(dactyl, modules) {
         const options = modules.options;
-        if (services.has("privateBrowsing"))
+        if (services.has("privateBrowsing") && "privateBrowsingEnabled" in services.privateBrowsing)
             options.add(["private", "pornmode"],
                 "Set the 'private browsing' option",
                 "boolean", false,
diff --git a/common/skin/global-styles.css b/common/skin/global-styles.css
index 45fe12b9..b09f4022 100644
--- a/common/skin/global-styles.css
+++ b/common/skin/global-styles.css
@@ -1,4 +1,3 @@
-
 Boolean      /* JavaScript booleans */       color: red;
 Function     /* JavaScript functions */      color: navy;
 Null         /* JavaScript null values */    color: blue;
@@ -77,6 +76,14 @@ StatusWarningMsg  /* A warning message in the status line */ \
 Disabled          /* Disabled items */ \
                   color: gray    !important;
 
+!Private;xul|window[privatebrowsingmode]  /* A private browsing window */
+
+Private StatusLine::before  /* From the default theme: */ \
+                            display: -moz-box; \
+                            content: ""; \
+                            background: url("chrome://browser/skin/privatebrowsing-mask.png") center no-repeat; \
+                            width: 30px;
+
 CmdLine;>*;;FontFixed   /* The command line */ \
                         padding: 1px !important;
 CmdPrompt;.dactyl-commandline-prompt  /* The default styling form the command prompt */