diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -3281,23 +3281,16 @@ XRE_main(int argc, char* argv[], const n
         }
         dirProvider.DoStartup();
 
         PRBool shuttingDown = PR_FALSE;
         appStartup->GetShuttingDown(&shuttingDown);
 
         nsCOMPtr<nsICommandLineRunner> cmdLine;
 
-#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK2)
-        nsRefPtr<nsGTKToolkit> toolkit = GetGTKToolkit();
-        if (toolkit && !desktopStartupID.IsEmpty()) {
-          toolkit->SetDesktopStartupID(desktopStartupID);
-        }
-#endif
-
         nsCOMPtr<nsIFile> workingDir;
         rv = NS_GetSpecialDirectory(NS_OS_CURRENT_WORKING_DIR, getter_AddRefs(workingDir));
         NS_ENSURE_SUCCESS(rv, 1);
 
         if (!shuttingDown) {
           cmdLine = do_CreateInstance("@mozilla.org/toolkit/command-line;1");
           NS_ENSURE_TRUE(cmdLine, 1);
 
@@ -3315,16 +3308,23 @@ XRE_main(int argc, char* argv[], const n
 
           NS_TIMELINE_ENTER("appStartup->CreateHiddenWindow");
           rv = appStartup->CreateHiddenWindow();
           NS_TIMELINE_LEAVE("appStartup->CreateHiddenWindow");
           NS_ENSURE_SUCCESS(rv, 1);
 
           MOZ_SPLASHSCREEN_UPDATE(50);
 
+#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK2)
+          nsRefPtr<nsGTKToolkit> toolkit = GetGTKToolkit();
+          if (toolkit && !desktopStartupID.IsEmpty()) {
+            toolkit->SetDesktopStartupID(desktopStartupID);
+          }
+#endif
+
           // Extension Compatibility Checking and Startup
           if (gAppData->flags & NS_XRE_ENABLE_EXTENSION_MANAGER) {
             nsCOMPtr<nsIExtensionManager> em(do_GetService("@mozilla.org/extensions/manager;1"));
             NS_ENSURE_TRUE(em, 1);
 
             if (upgraded) {
               rv = em->CheckForMismatches(&needsRestart);
               if (NS_FAILED(rv)) {
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -3602,30 +3602,23 @@ XRE_main(int argc, char* argv[], const n
 #ifdef XP_MACOSX
       if (gBinaryPath) {
         static char kEnvVar[MAXPATHLEN];
         sprintf(kEnvVar, "XRE_BINARY_PATH=%s", gBinaryPath);
         PR_SetEnv(kEnvVar);
       }
 #endif
 
-// XXXkt s/MOZ_TOOLKIT_GTK2/MOZ_WIDGET_GTK2/?
-// but the hidden window has been destroyed so toolkit is NULL anyway.
-#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_TOOLKIT_GTK2)
-      nsGTKToolkit* toolkit = GetGTKToolkit();
-      if (toolkit) {
-        nsCAutoString currentDesktopStartupID;
-        toolkit->GetDesktopStartupID(&currentDesktopStartupID);
-        if (!currentDesktopStartupID.IsEmpty()) {
-          nsCAutoString desktopStartupEnv;
-          desktopStartupEnv.AssignLiteral("DESKTOP_STARTUP_ID=");
-          desktopStartupEnv.Append(currentDesktopStartupID);
-          // Leak it with extreme prejudice!
-          PR_SetEnv(ToNewCString(desktopStartupEnv));
-        }
+#if defined(HAVE_DESKTOP_STARTUP_ID) && defined(MOZ_WIDGET_GTK2)
+      if (!desktopStartupID.IsEmpty()) {
+        nsCAutoString desktopStartupEnv;
+        desktopStartupEnv.AssignLiteral("DESKTOP_STARTUP_ID=");
+        desktopStartupEnv.Append(desktopStartupID);
+        // Leak it with extreme prejudice!
+        PR_SetEnv(ToNewCString(desktopStartupEnv));
       }
 #endif
 
 #ifdef MOZ_WIDGET_GTK2
       MOZ_gdk_display_close(display);
 #endif
 
       rv = LaunchChild(nativeApp, appInitiatedRestart);