I tested with this Track Changes demo
, but to no avail. Pasting is working as expected. Which is the browser used? Are you able to reproduce the same issue with the online demo?
If you are still unable to find the source of the problem, you can provide a sample with which teh issue is reproducible, so that I could investigate the issue on my end.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.