diff --git a/native/userchrome/profile/chrome/pwa/boot.jsm b/native/userchrome/profile/chrome/pwa/boot.jsm
index 3e93c528..b6ea1d1f 100644
--- a/native/userchrome/profile/chrome/pwa/boot.jsm
+++ b/native/userchrome/profile/chrome/pwa/boot.jsm
@@ -120,7 +120,8 @@ function launchSite (siteConfig, urlList, isStartup) {
 // Properly disable Firefox Session Restore and Private Window Separation
 Services.prefs.getDefaultBranch(null).setBoolPref('browser.sessionstore.resume_from_crash', false);
 Services.prefs.getDefaultBranch(null).setIntPref('browser.sessionstore.max_resumed_crashes', 0);
-Services.prefs.getDefaultBranch(null).setIntPref('browser.sessionstore.idleDelay', -1);
+Services.prefs.getDefaultBranch(null).setIntPref('browser.sessionstore.max_tabs_undo', 0);
+Services.prefs.getDefaultBranch(null).setIntPref('browser.sessionstore.max_windows_undo', 0);
 Services.prefs.getDefaultBranch(null).setBoolPref('browser.privateWindowSeparation.enabled', false);
 Services.prefs.getDefaultBranch(null).setBoolPref('browser.privacySegmentation.createdShortcut', true);
 
diff --git a/native/userchrome/profile/chrome/pwa/content/browser.jsm b/native/userchrome/profile/chrome/pwa/content/browser.jsm
index da27c165..fdb3ea41 100644
--- a/native/userchrome/profile/chrome/pwa/content/browser.jsm
+++ b/native/userchrome/profile/chrome/pwa/content/browser.jsm
@@ -1887,7 +1887,8 @@ class PwaBrowser {
     xPref.set('browser.tabs.warnOnClose', false, true);
     xPref.set('browser.sessionstore.resume_from_crash', false, true);
     xPref.set('browser.sessionstore.max_resumed_crashes', 0, true);
-    xPref.set('browser.sessionstore.idleDelay', -1, true);
+    xPref.set('browser.sessionstore.max_tabs_undo', 0, true);
+    xPref.set('browser.sessionstore.max_windows_undo', 0, true);
     xPref.set('browser.shell.checkDefaultBrowser', false, true);
     xPref.set('browser.startup.upgradeDialog.enabled', false, true);
     xPref.set('browser.aboutwelcome.enabled', false, true);