diff --git a/browser/base/content/browser.xhtml b/browser/base/content/browser.xhtml
index 5dd337a2ffc9f9107d735f4dc96a50d57b12d213..58ecaf7136e13885ac38d74d40b5ef0f52cd7684 100644
--- a/browser/base/content/browser.xhtml
+++ b/browser/base/content/browser.xhtml
@@ -98,6 +98,8 @@
 
   <title data-l10n-id="browser-main-window-title"></title>
 
+#include zen-preloaded.inc.xhtml
+
 # All JS files which are needed by browser.xhtml and other top level windows to
 # support MacOS specific features *must* go into the global-scripts.inc file so
 # that they can be shared with macWindow.inc.xhtml.
@@ -141,6 +143,7 @@
   window.addEventListener("DOMContentLoaded",
     gBrowserInit.onDOMContentLoaded.bind(gBrowserInit), { once: true });
 </script>
+#include zen-assets.inc.xhtml
 </head>
 <html:body xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 # All sets except for popupsets (commands, keys, and stringbundles)
@@ -162,9 +165,12 @@
     </vbox>
   </html:template>
 
-#include navigator-toolbox.inc.xhtml
-
-#include browser-box.inc.xhtml
+  <hbox id="zen-main-app-wrapper" flex="1">
+    #include navigator-toolbox.inc.xhtml
+    <html:span id="zen-sidebar-box-container">
+    </html:span>
+    #include browser-box.inc.xhtml    
+  </hbox>
 
   <html:template id="customizationPanel">
     <box id="customization-container" flex="1" hidden="true"><![CDATA[