Hi Sashekumar,
Thank you for your interest in Syncfusion products.
Could you please let us know what type of event you are using to popup the window whether Server side or Client side?
If your intension is to trigger an event after the node is dragged, we suggest you to use “NodeDrop” server side event to trigger the event after a node dropped on the diagram control. You can find more information about these events in the online documentation link from below.
http://help.syncfusion.com/ug_83/User%20Interface/ASP.NET/Diagram/Documents/serversideevents.htmPlease let me know if any concerns. Please let me know if I have misunderstood your query
Regards,
Vijayabharathi K