Hi Anh,
Greetings from syncfusion support
From your update we could see that the horizontal scrollbar was moved to left when you open the context menu. Based on your reported scenario we have checked it from our end and try to reproduce your reported problem. But it was unsuccessful. For your reference we have attached the sample and video demo.
If you still face the issue, Please share the below details that will be helpful for us to provide better solution.
1) Please share your exact requirement with detailed description.
2) Share an issue replication procedure step by step.
3) Please share issue scenario in video demonstration format.
4) Please share your syncfusion package version.
5) Please confirm what action you have performed in the contextMenu.
6) Please share any issue reproducible sample or please modify the above sample as per your application structure and try to reproduce the issue.
Regards,
Rajapandi R