Not sure what Ankita wants to demonstrate with this sample.

It's different from the original by the way dimension values are related to higher dimensions. For example, each user is related to only one single role. But the sorting issue will only be visible if you have a 1:n relation, e.g. a user is related to more than one role. In Ankita's original post, the empty or blank role shows this issue because it's related to many departments.

Timanshu, I don't think your solution will work. Try with a simple sample I've attached (try to sort Field2).