diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index 30d14d9231b7..16c4be52a1f9 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -5539,7 +5539,7 @@ if (SpecialPowers.getBoolPref("layout.css.isolation.enabled")) {
     inherited: false,
     type: CSS_TYPE_LONGHAND,
     initial_values: [ "auto" ],
-    other_values: ["isolated"],
+    other_values: ["isolate"],
     invalid_values: []
   };
 }