diff --git a/resources/prefs.json b/resources/prefs.json
index c0f92f9e..2718d7e7 100644
--- a/resources/prefs.json
+++ b/resources/prefs.json
@@ -103,7 +103,7 @@
   "js.werror.enabled": false,
   "layout.animations.test.enabled": false,
   "layout.columns.enabled": false,
-  "layout.flexbox.enabled": false,
+  "layout.flexbox.enabled": true,
   "layout.legacy_layout": false,
   "layout.tables.enabled": false,
   "layout.threads": 3,