BulkEditSave() is never called by Ajax.Update

I am working on NopCommerce 2.5 / Admin/ProductVariant/BulkEdit page. I can see the Ajax function calling "http://localhost.:62904/Admin/ProductVariant/BulkEdit#" whenever I changed the value in this page. However, it did not hit the function to update. Because this "dataBinding.Ajax().Update("BulkEditSave", "ProductVariant")" never call the controller logic, changed value is not updated in the database as well. What could be happened on this view and controller?
So far no luck even though I checked with Telerik's document. Thanks in advance.

Everything works fine (test it here). I presume you modified source code or did not upload all files when deploying