In TFS 2010 a requirement work item had also an implementation and a change request tab.
See https://i-msdn.sec.s-msft.com/dynimg/IC361365.png
In TFS 2012 the requirement work item also had an implementation and change request tab as written in the documentation https://msdn.microsoft.com/en-us/library/ee332491(v=vs.110).aspx, but the picture of a newly created requirement doesn't show anymore these tabs.
Now, in TFS 2015 those two tabse aren't mentioned any more, though the CMMI process shows the work item hierachy as Epic > Feature > Requirement > Task
I am missing the implementation and change request tab in the standard configuration the CMMI project, because they are very useful in tracking the whole work from defining the features down to the requirements and their implementation with testing as well as subsequent change requests.
Are there any ways to get back these tabs in the standard configuration? I don't like to change the predefined work item types, because you never now what happens with next upgrades of TFS.