> There is more than one way that you can find yourself in this sort
> apparent dilemma, and it is unclear from your question with which
> problem you are struggling. Most commonly this sort of confusion
> because the designer is trying to model the workflow or a business
> rather than the interactive needs of some users in particular roles.
Sorry for the vagueness. This is involving two (or more)
simultaneous users on different machines. Related to instant
messaging. The user may initiate an action which will affect the
other user(s) or (more importantly as far as I understand use cases)
the other user(s) could initiate the action which will affect what
this user sees and has to respond to.
As I understand it, both users are in essentially the same role. It
may just be different use cases depending whether the role initiates
the action or whether it's initiated by someone else.
> Aside from these more common confusions of workflow with
> yet another possibility is an attempt to cover more than one
> case in a single description. In these cases, decomposing
> extensions is usually the cleanest solution.
> The relationships among scenarios, tasks, use cases, and essential
> is discussed in some detail in a new paper
I've printed out most of your PDFs and Application Notes. I'm still
a little shaky on the different relationships between use cases (when
to use extensions vs. specializations vs. composition vs. affinities)
but now that I think I've got my roles straightened out, I'm going to
push my way through use cases next.