diff --git a/toolkit/mozapps/downloads/content/downloads.js b/toolkit/mozapps/downloads/content/downloads.js
index 05d1b72bf48..a4ee0e7dc80 100644
--- a/toolkit/mozapps/downloads/content/downloads.js
+++ b/toolkit/mozapps/downloads/content/downloads.js
@@ -504,6 +504,15 @@ let gDownloadObserver = {
         break;
       case "private-browsing":
         if (aData == "enter" || aData == "exit") {
+          // We need to reset the title here, because otherwise the title of
+          // the download manager would still reflect the progress of current
+          // active downloads, if any, after switchiung the private browsing
+          // mode, even though the downloads will no longer be accessible.
+          // If any download is auto-started after switching the private
+          // browsing mode, the title will be updated as needed by the progress
+          // listener.
+          document.title = document.documentElement.getAttribute("statictitle");
+
           // We might get this notification before the download manager
           // service, so the new database connection might not be ready
           // yet.  Defer this until all private-browsing notifications
diff --git a/toolkit/mozapps/downloads/tests/chrome/Makefile.in b/toolkit/mozapps/downloads/tests/chrome/Makefile.in
index 0661b4468a7..cf443119374 100644
--- a/toolkit/mozapps/downloads/tests/chrome/Makefile.in
+++ b/toolkit/mozapps/downloads/tests/chrome/Makefile.in
@@ -62,6 +62,7 @@ _CHROME_FILES = \
   test_search_keys.xul \
   test_select_all.xul \
   test_space_key_pauses_resumes.xul \
+  test_privatebrowsing_title.xul \
   test_ui_stays_open_on_alert_clickback.xul \
   test_unkownContentType_dialog_layout.xul \
   test_bug_412360.xul \
diff --git a/toolkit/mozapps/downloads/tests/chrome/test_privatebrowsing_title.xul b/toolkit/mozapps/downloads/tests/chrome/test_privatebrowsing_title.xul
new file mode 100644
index 00000000000..dca24ce6a33
--- /dev/null
+++ b/toolkit/mozapps/downloads/tests/chrome/test_privatebrowsing_title.xul
@@ -0,0 +1,139 @@
+<?xml version="1.0"?>
+<!--
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Download Manager UI Test Code.
+ *
+ * The Initial Developer of the Original Code is
+ * Ehsan Akhgari <ehsan.akhgari@gmail.com>.
+ * Portions created by the Initial Developer are Copyright (C) 2009
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+/**
+ * Test bug 464800 to make sure that the download manager window title is
+ * properly cleared when transitioning into the private browsing mode.
+ */
+-->
+
+<window title="Private Browsing transition title change test"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="test();">
+
+  <script type="application/javascript"
+          src="chrome://mochikit/content/MochiKit/packed.js"/>
+  <script type="application/javascript"
+          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script type="application/javascript"
+          src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+
+  <script type="application/javascript">
+  <![CDATA[
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cr = Components.results;
+
+function test()
+{
+  // The private browsing service might not be available
+  let pbs = null;
+  try {
+    pbs = Cc["@mozilla.org/privatebrowsing;1"].getService(Ci.nsIPrivateBrowsingService);
+  } catch (e) {
+  }
+  if (!pbs)
+    return;
+
+  // We should prevent the private browsing service from changing the current
+  // session on private mode transitions, in order to play nice with the
+  // Mochitest test harness.
+  let prefBranch = Cc["@mozilla.org/preferences-service;1"].
+                   getService(Ci.nsIPrefBranch);
+  prefBranch.setBoolPref("browser.privatebrowsing.keep_current_session", true);
+
+  // Close the UI if necessary
+  let wm = Cc["@mozilla.org/appshell/window-mediator;1"].
+           getService(Ci.nsIWindowMediator);
+  let win = wm.getMostRecentWindow("Download:Manager");
+  if (win) win.close();
+
+  let obs = Cc["@mozilla.org/observer-service;1"].
+            getService(Ci.nsIObserverService);
+  const DLMGR_UI_DONE = "download-manager-ui-done";
+
+  let testObs = {
+    observe: function(aSubject, aTopic, aData) {
+      if (aTopic != DLMGR_UI_DONE)
+        return;
+
+      let win = aSubject.QueryInterface(Ci.nsIDOMWindow);
+      let defaultTitle = win.document.documentElement.getAttribute("statictitle");
+      is(win.document.title, defaultTitle,
+        "The downloads window title is correct outside of the private browsing mode");
+      win.document.title = "some title";
+
+      // Enter the private browsing mode
+      pbs.privateBrowsingEnabled = true;
+
+      is(win.document.title, defaultTitle,
+        "The downloads window title is correct inside the private browsing mode");
+      win.document.title = "another title";
+
+      // Leave the private browsing mode
+      pbs.privateBrowsingEnabled = false;
+
+      is(win.document.title, defaultTitle,
+        "The downloads window title is correct after leaving the private browsing mode");
+
+      // We're done!
+      win.close();
+      obs.removeObserver(testObs, DLMGR_UI_DONE);
+      prefBranch.clearUserPref("browser.privatebrowsing.keep_current_session");
+      SimpleTest.finish();
+    }
+  };
+  obs.addObserver(testObs, DLMGR_UI_DONE, false);
+
+  // Show the Download Manager UI
+  Cc["@mozilla.org/download-manager-ui;1"].
+  getService(Ci.nsIDownloadManagerUI).show();
+
+  SimpleTest.waitForExplicitFinish();
+}
+
+  ]]>
+  </script>
+
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display:none;"></div>
+    <pre id="test"></pre>
+  </body>
+</window>