diff --git a/lib/manifest.js b/lib/manifest.js
index e09072a..9a9ee33 100644
--- a/lib/manifest.js
+++ b/lib/manifest.js
@@ -30,7 +30,7 @@ function getDefaultManifestAttributes (manifest, production) {
       return {
         content_security_policy: {
           extension_pages: "script-src 'self'; object-src 'self'",
-          sandbox: "script-src 'self'" + (production ? '' : " 'unsafe-eval'") + "; object-src 'self'"
+          sandbox: "sandbox allow-scripts allow-forms allow-popups allow-modals; script-src 'self' 'unsafe-inline' 'unsafe-eval'; child-src 'self';"
         }
       }