Concurrent Development 

Concurrency Control means managing multiple users who simultaneously carry out different modifications on the same development resource.

During concurrent development, there can be more than one user working on the same resource. Using the DTR, it is possible for more than one user to check out the same resource from the workspace and carry out changes. A foreign checkout icon on the resource depicts the checkout of a resource by any other user. In this case, you can still check out the resource, as long as you don’t check it out exclusively. For more information, refer to Modifying a Versioned Resource.

When you develop concurrently and then try to check in your changes, conflicts can occur: The DTR automatically recognizes such check-in conflicts.