This was the first question I had from my editorial manager who was using a test system I built. He created a user account, didn't assign a role, then couldn't find the account again to enroll it. I couldn't intuit solution from the user interface either, and jumped into postgres to do 'SELECT * FROM users;" to be certain the user had actually been created. When I created my test accounts, I immediately assigned roles and so wasn't bitten by this.
Thoughts on cleaning up the user interface:
The "All Users" link in the "Users" section on the "Journal Management" page should probably be labelled "Enrollment", as that's the title of the page to which the link leads. Most other pages have titles matching their respective links.
On the "Enrollment" page itself, the section title "All Users" should probably be changed to "Search" or something to that effect. What meaning does "All Users" have above the search interface? The user is about to select a role category for searching, which isn't related to "All Users". Further, the "All Users" entry in the drop down list should probably be changed to "All Roles", such that it's clearer we're searching roles, not users.
I do think, at a minimum, the Enrollment page should also provide a mechanism to enroll currently unenrolled users. After all, the page is titled "Enrollment". It is confusing that the Enrollment page is really (and only) for managing currently enrolled users, i.e. editing roles, assuming a user role, etc.
A reasonable solution might be to place the "Enroll Existing User" link on the Journal Managment page, with the "All Users" (which should still be renamed, as above
), "Create New User", etc. links. Otherwise, the "Enroll Existing User" link is too obscure (being at the bottom of a page which really seems designed to be doing exactly that..).
I think OJS does a nice job of divorcing user accounts from roles, which is quite helpful. There just needs to be a bit of clarification to users (and administrators!).
I hope this makes some sense, it would be easier to convey with screenshots.