title: TFS: Why do Issues appear on the Backlog?
body: <p>We are using TFS 2015 together with the CMMI process template and I have just found out that Issues do appear on the backlog if they are a child of a Feature or a Requirement work item type. If the Issue is standalone (has not link to one of the two mentioned work item types) it is not visible on the backlog.</p>
  
  <p>I guess that someone has made some hacks here in order to make this possible. Originally, only Epics, Features, Requirements, Tasks, and Bugs should appear on the backlog.</p>
  
  <p>I have checked the Issue work item type definition as well as the processconfiguration.xml and the categories.xml which look quite ok from my point of view.</p>
  
  <p>Are there any another places where one could define which work item types should be visible on the backlog?</p>
  
  <p>Thanks a lot for giving support.</p>