diff --git a/rollup.base.config.js b/rollup.base.config.js
index 9018ed432..b261c326b 100644
--- a/rollup.base.config.js
+++ b/rollup.base.config.js
@@ -169,7 +169,7 @@ const browserRollupConfigFactory = (banner, importCheckNames, targetType, theNam
             uglify({
                 ie8: true,
                 ie: true,
-                toplevel: true,
+                toplevel: false,
                 compress: {
                     ie: true,
                     passes:3,