diff --git a/browser/components/about/AboutRedirector.cpp b/browser/components/about/AboutRedirector.cpp
index 446a0a0e0bd5..891580928fe6 100644
--- a/browser/components/about/AboutRedirector.cpp
+++ b/browser/components/about/AboutRedirector.cpp
@@ -95,7 +95,7 @@ static RedirEntry kRedirMap[] = {
     nsIAboutModule::ALLOW_SCRIPT },
   { "app-manager", "chrome://browser/content/devtools/app-manager/index.xul",
     nsIAboutModule::ALLOW_SCRIPT },
-  { "customizing", "chrome://browser/content/customizableui/aboutCustomizing.xhtml",
+  { "customizing", "chrome://browser/content/customizableui/aboutCustomizing.xul",
     nsIAboutModule::ALLOW_SCRIPT },
 };
 static const int kRedirTotal = ArrayLength(kRedirMap);
diff --git a/browser/components/customizableui/content/aboutCustomizing.xhtml b/browser/components/customizableui/content/aboutCustomizing.xul
similarity index 51%
rename from browser/components/customizableui/content/aboutCustomizing.xhtml
rename to browser/components/customizableui/content/aboutCustomizing.xul
index 14d82d0f99d1..65448d1821ba 100644
--- a/browser/components/customizableui/content/aboutCustomizing.xhtml
+++ b/browser/components/customizableui/content/aboutCustomizing.xul
@@ -1,25 +1,22 @@
 <?xml version="1.0" encoding="UTF-8"?>
+
 <!-- 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/. -->
 
-<!DOCTYPE html [
-  <!ENTITY % htmlDTD
-    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
-    "DTD/xhtml1-strict.dtd">
-  %htmlDTD;
+<!DOCTYPE window [
   <!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
   %brandDTD;
   <!ENTITY % browserDTD SYSTEM "chrome://browser/locale/browser.dtd">
   %browserDTD;
 ]>
 
-<html xmlns="http://www.w3.org/1999/xhtml"
-      disablefastfind="true">
-	<head>
-		<title>&customizeMode.tabTitle;</title>
-		<link rel="icon" type="image/x-icon"
-		      href="chrome://browser/skin/customizableui/customizeFavicon.ico"/>
-	</head>
-	<body></body>
-</html>
+<window id="aboutCustomizingWindow"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        xmlns:html="http://www.w3.org/1999/xhtml"
+        title="&customizeMode.tabTitle;">
+  <html:head>
+    <html:link rel="icon" type="image/x-icon"
+               href="chrome://browser/skin/customizableui/customizeFavicon.ico"/>
+  </html:head>
+</window>
diff --git a/browser/components/customizableui/content/jar.mn b/browser/components/customizableui/content/jar.mn
index 866efd3cc60a..412bd755d1f7 100644
--- a/browser/components/customizableui/content/jar.mn
+++ b/browser/components/customizableui/content/jar.mn
@@ -3,7 +3,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 browser.jar:
-  content/browser/customizableui/aboutCustomizing.xhtml
+  content/browser/customizableui/aboutCustomizing.xul
   content/browser/customizableui/panelUI.css
 * content/browser/customizableui/panelUI.js
   content/browser/customizableui/panelUI.xml
