diff --git a/dynamic_native_tabs.css b/dynamic_native_tabs.css
index d7b5989..c876959 100644
--- a/dynamic_native_tabs.css
+++ b/dynamic_native_tabs.css
@@ -17,11 +17,11 @@
 }
 
 /* Hidden state: Hide native tabs strip */
-#main-window[titlepreface*="XXX"] #titlebar {
+#main-window[titlepreface*="​"] #titlebar {
     height: 0 !important;
 }
 
 /* Hidden state: Fix z-index of active pinned tabs */
-#main-window[titlepreface*="XXX"] #tabbrowser-tabs {
+#main-window[titlepreface*="​"] #tabbrowser-tabs {
     z-index: 0 !important;
 }
\ No newline at end of file