Q:
I would like to make self running demos with Diagram and ShowAndTell under NS3.0.
A:
ShowAndTell does not work with many kinds of event loops and therefore is not well suited for Diagram! and some other applications. NeXT does not ship the example program ShowAndTell in 3.0 for this reason. There may be other third party software that records sessions on the NeXT. See your NeXTSTEP Third Party Catalog.
Valid for 2.x