Hi Lan,
Thanks for your updates and sorry for the inconvenience caused.
The reported issue has been suspected to be a defect. Please create a DT incident for your query so that we can update the patch for this issue.
You can create the DT incident from the following link.
http://www.syncfusion.com/account/dashboardIn the interests of maintaining confidentiality, we have a policy of not sharing patches or otherwise proprietary customer specific information in the public Forum.
Please let us know if you have any queries.
Regards,
Senthilkumar.M