I was trying to enable assigning work items to a group on TFS 2010, and after following Ivan Fioravanti’s excellent Blog Post on the subject, I still found that my Team Project groups were not appearing in the “Assigned To” dropdown list. After triple checking everything, I noticed the most important point on his blog: “remove VALIDUSER rule, because this is responsible for not showing groups in the dropdown list”. I checked again, and yep, the System.AssignedTo field did not have that rule. After a little thinking I eventually searched my Work Item Template Definition XML for the term “VALIDUSER” and bingo, there was another one!

It turned out I also had a “VALIDUSER” rule applied to the initial state transition (i.e. from “” to “New”) for the System.AssignedTo field.

This was ensuring that all newly logged bugs must be assigned to a User, and not a Group. If I were testing my change on an existing work item, I would not have noticed the problem.

I removed the extra VALIDUSER – probably added in a moment of over eagerness – and hey presto, everything worked as Ivan said it would!