diff --git a/chrome/autohide_sidebar.css b/chrome/autohide_sidebar.css
index c3c0d07..e673aa3 100644
--- a/chrome/autohide_sidebar.css
+++ b/chrome/autohide_sidebar.css
@@ -145,4 +145,9 @@ See the above repository for updates as well as full license text. */
     transform: translateX(calc(var(--uc-sidebar-hover-width) - var(--uc-sidebar-width)));
     transition-delay: 0ms !important;
   }
-}
\ No newline at end of file
+}
+@media -moz-pref("userchrome.autohide-sidebar.hide-main-sidebar"){
+  #sidebar-main[sidebar-panel-open]{
+    contain: strict;
+  }
+}