diff --git a/mozilla/browser/base/content/browser-places.js b/mozilla/browser/base/content/browser-places.js
index 8e9671d12cd..f682db05a19 100644
--- a/mozilla/browser/base/content/browser-places.js
+++ b/mozilla/browser/base/content/browser-places.js
@@ -52,6 +52,9 @@ var PlacesCommandHook = {
   get panel() {
     delete this.panel;
     var element = document.getElementById("editBookmarkPanel");
+    // initially the panel is hidden
+    // to avoid impacting startup / new window performance
+    element.hidden = false;
     element.addEventListener("popuphiding", this, false);
     element.addEventListener("keypress", this, true);
     return this.panel = element;
diff --git a/mozilla/browser/base/content/browser.xul b/mozilla/browser/base/content/browser.xul
index 117dbedeaf3..ece22695ae3 100644
--- a/mozilla/browser/base/content/browser.xul
+++ b/mozilla/browser/base/content/browser.xul
@@ -99,9 +99,9 @@
            onclick="checkForMiddleClick(this, event);"/>
     <tooltip id="aHTMLTooltip" onpopupshowing="return FillInHTMLTooltip(document.tooltipNode);"/>
 
-    <panel type="autocomplete" chromedir="&locale.dir;" id="PopupAutoComplete" noautofocus="true"/>
+    <panel type="autocomplete" chromedir="&locale.dir;" id="PopupAutoComplete" noautofocus="true" hidden="true"/>
 
-    <panel id="editBookmarkPanel" orient="vertical">
+    <panel id="editBookmarkPanel" orient="vertical" hidden="true">
       <vbox id="editBookmarkPanelContent" flex="1"/>
       <hbox flex="1">
         <spacer flex="1"/>
diff --git a/mozilla/browser/base/content/urlbarBindings.xml b/mozilla/browser/base/content/urlbarBindings.xml
index 3d0ea89bc15..29d5e879233 100644
--- a/mozilla/browser/base/content/urlbarBindings.xml
+++ b/mozilla/browser/base/content/urlbarBindings.xml
@@ -221,6 +221,19 @@
 
   <binding id="urlbar-result-popup" extends="chrome://global/content/bindings/autocomplete.xml#autocomplete-result-popup">
     <implementation>
+      <method name="openAutocompletePopup">
+        <parameter name="aInput"/>
+        <parameter name="aElement"/>
+        <body><![CDATA[
+          // initially the panel is hidden
+          // to avoid impacting startup / new window performance
+          aInput.popup.hidden = false;
+
+          // this method is defined on the base binding
+          this._openAutocompletePopup(aInput, aElement);
+        ]]></body>
+      </method>
+
       <method name="onPopupClick">
         <parameter name="aEvent"/>
         <body><![CDATA[
diff --git a/mozilla/toolkit/content/widgets/autocomplete.xml b/mozilla/toolkit/content/widgets/autocomplete.xml
index 5d38813693d..009886e3c6e 100644
--- a/mozilla/toolkit/content/widgets/autocomplete.xml
+++ b/mozilla/toolkit/content/widgets/autocomplete.xml
@@ -570,6 +570,17 @@
                 onget="return this.mPopupOpen;"/>
 
       <method name="openAutocompletePopup">
+        <parameter name="aInput"/>
+        <parameter name="aElement"/>
+        <body><![CDATA[
+          // until we have "baseBinding", (see bug #373652) this allows
+          // us to override openAutocompletePopup(), but still call
+          // the method on the base class
+          this._openAutocompletePopup(aInput, aElement);
+        ]]></body>
+      </method>
+
+      <method name="_openAutocompletePopup">
         <parameter name="aInput"/>
         <parameter name="aElement"/>
         <body><![CDATA[
