Hi Mounika,
Reported Issue : Context menu is not rendered in blazor
The contextMenu is not working in our diagram control. We have confirmed this as a defect. We have logged a defect report for this issue. We will fix this issue and provide the patch on volume 1, release which is scheduled to release by the end of March, 2020.
Now, you can track the status of your issue through below feedback link.
Regards
Shyam G