I can't see a user in watchers or mention it in comments.

[AnPa]

Have created a user that has the same settings as many other users, but when I try to add the user to watchers, it does not appear. Can't specify the person in comments either.

The user enters the project, can both view and create issues, but no one else can add the user to watchers. Which setting have I missed?

[Matt Parks]

Is the user in a group that is specifically granted the 'Watch Issues' permission for that particular project? I don't know what  permission, if any allows users to be mentioned in comments, but I do know that the user needs to have the 'Watch Issues' permission in the Permission Scheme in order to be able to be added to the list of watchers.