Hi Russ,
You're right, this is a global variable VI. Global VIs do not have diagrams. Once you change the values, you can go to Operate > Make Current Values Default, then save the VI. Your values will now be persisted the next time you open the VI.
I also recommend re-naming the file to have a .vi extension, since Global VIs are, well, VIs!
Let me know if you have any other questions on this topic.
-D