Post button doesn’t show on GW appt.

I work on a help desk and get calls on a “problem” that our Netware admin can’t figure out. We’re running Groupwise 6.0. Some branches cannot see the Post button when editing calendar appointments. The only buttons they see on the right are Close and Delete. At another branch, they also see Post. Of course, a user can click the Action menu and choose Post, but they get confused when, in training, they’re told about the Post button. So, what can we do to get this button to show?