diff --git a/browser/base/content/browser-init.js b/browser/base/content/browser-init.js
index 3d5173315812589c0b79beec5f0419fc37cb8868..c4216db9e414fbbaead6ecd89b40366b0d8a50c1 100644
--- a/browser/base/content/browser-init.js
+++ b/browser/base/content/browser-init.js
@@ -175,6 +175,8 @@ var gBrowserInit = {
   },
 
   onLoad() {
+    Services.scriptloader.loadSubScript("chrome://browser/content/ZenStartup.mjs", window);
+    Services.scriptloader.loadSubScript("chrome://browser/content/zenThemeModifier.js", window);
     gBrowser.addEventListener("DOMUpdateBlockedPopups", e =>
       PopupBlockerObserver.handleEvent(e)
     );
@@ -310,6 +312,7 @@ var gBrowserInit = {
     TelemetryTimestamps.add("delayedStartupStarted");
 
     this._cancelDelayedStartup();
+    ZenWorkspaces.afterLoadInit();
 
     gBrowser.addEventListener(
       "PermissionStateChange",
