--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -13,17 +13,16 @@ const nsIWebNavigation = Ci.nsIWebNaviga
 var gCharsetMenu = null;
 var gLastBrowserCharset = null;
 var gPrevCharset = null;
 var gProxyFavIcon = null;
 var gLastValidURLStr = "";
 var gInPrintPreviewMode = false;
 var gDownloadMgr = null;
 var gContextMenu = null; // nsContextMenu instance
-var gDelayedStartupTimeoutId;
 var gStartupRan = false;
 
 #ifndef XP_MACOSX
 var gEditUIVisible = true;
 #endif
 
 [
   ["gBrowser",            "content"],
@@ -1237,26 +1236,35 @@ var gBrowserInit = {
     CombinedStopReload.init();
     allTabs.readPref();
     TabsOnTop.init();
     BookmarksMenuButton.init();
     TabsInTitlebar.init();
     gPrivateBrowsingUI.init();
     retrieveToolbarIconsizesFromTheme();
 
-    gDelayedStartupTimeoutId = setTimeout(this._delayedStartup.bind(this), 0, isLoadingBlank, mustLoadSidebar);
+    // Wait until chrome is painted before executing code not critical to making the window visible
+    this._boundDelayedStartup = this._delayedStartup.bind(this, isLoadingBlank, mustLoadSidebar);
+    window.addEventListener("MozAfterPaint", this._boundDelayedStartup);
+
     gStartupRan = true;
   },
 
+  _cancelDelayedStartup: function () {
+    window.removeEventListener("MozAfterPaint", this._boundDelayedStartup);
+    this._boundDelayedStartup = null;
+  },
+
   _delayedStartup: function(isLoadingBlank, mustLoadSidebar) {
     let tmp = {};
     Cu.import("resource:///modules/TelemetryTimestamps.jsm", tmp);
     let TelemetryTimestamps = tmp.TelemetryTimestamps;
     TelemetryTimestamps.add("delayedStartupStarted");
-    gDelayedStartupTimeoutId = null;
+
+    this._cancelDelayedStartup();
 
 #ifdef MOZ_SAFE_BROWSING
     // Bug 778855 - Perf regression if we do this here. To be addressed in bug 779008.
     setTimeout(function() { SafeBrowsing.init(); }, 2000);
 #endif
 
     Services.obs.addObserver(gSessionHistoryObserver, "browser:purge-session-history", false);
     Services.obs.addObserver(gXPInstallObserver, "addon-install-disabled", false);
@@ -1581,18 +1589,18 @@ var gBrowserInit = {
       document.persist("sidebar-box", "sidebarcommand");
       document.persist("sidebar-box", "width");
       document.persist("sidebar-box", "src");
       document.persist("sidebar-title", "value");
     }
 
     // Now either cancel delayedStartup, or clean up the services initialized from
     // it.
-    if (gDelayedStartupTimeoutId) {
-      clearTimeout(gDelayedStartupTimeoutId);
+    if (this._boundDelayedStartup) {
+      this._cancelDelayedStartup();
     } else {
       if (Win7Features)
         Win7Features.onCloseWindow();
 
       gPrefService.removeObserver(ctrlTab.prefName, ctrlTab);
       gPrefService.removeObserver(allTabs.prefName, allTabs);
       ctrlTab.uninit();
       TabView.uninit();
@@ -1679,21 +1687,21 @@ var gBrowserInit = {
                             .getService(Ci.nsIMacDockSupport);
           dockSupport.dockMenu = nativeMenu;
         }
         catch (e) {
         }
       }
     }
 
-    gDelayedStartupTimeoutId = setTimeout(this.nonBrowserWindowDelayedStartup.bind(this), 0);
+    this._delayedStartupTimeoutId = setTimeout(this.nonBrowserWindowDelayedStartup.bind(this), 0);
   },
 
   nonBrowserWindowDelayedStartup: function() {
-    gDelayedStartupTimeoutId = null;
+    this._delayedStartupTimeoutId = null;
 
     // initialise the offline listener
     BrowserOffline.init();
 
     // Set up Sanitize Item
     this._initializeSanitizer();
 
     // initialize the private browsing UI
@@ -1705,18 +1713,18 @@ var gBrowserInit = {
 #endif
 
     gStartupRan = true;
   },
 
   nonBrowserWindowShutdown: function() {
     // If nonBrowserWindowDelayedStartup hasn't run yet, we have no work to do -
     // just cancel the pending timeout and return;
-    if (gDelayedStartupTimeoutId) {
-      clearTimeout(gDelayedStartupTimeoutId);
+    if (this._delayedStartupTimeoutId) {
+      clearTimeout(this._delayedStartupTimeoutId);
       return;
     }
 
     BrowserOffline.uninit();
 
 #ifndef MOZ_PER_WINDOW_PRIVATE_BROWSING
     gPrivateBrowsingUI.uninit();
 #endif