Hi Jangbok,
Thanks for the update.
The reported issue with TabControlAdv is a known issue under Tools Windows Forms, and you can download the patch details for the same from the following location.
https://s3.amazonaws.com/files2.syncfusion.com/Installs/v9.2.0.137/releasenotes/ui.html#Patch-DetailsPlease let us know if you need further assistance.
Regards,
Iniyen M.A.