Hi Ashok,
Sorry for the delay in updating you.
I was able to reproduce the mentioned issue i.e middlepoint between the two points was also shown as the PointIndex while using Tooltip.
Please try the attached sample which helps you to display the PointIndex correctly which I achieved through PrepareStyle Event.
But I was not able to control the dragging effect on the middlepoint. I am still working on this and let you know at the earliest once it is resolved.
Thank you for your patience.
Regards,
Jaya
GraphDrag0.zip