Sequence Diagrams: When Add to Base is grayed out

I'm trying to add a Sequence Diagram to my UML drawing packet using version 0.26. I have a Class diagram with 21 classes defined. When I try to create the first ClassifierRole in the Sequence diagram, it's created okay. But when I try to right click in the Properties tab, Base field, the two popup menu choices are Add... and Remove, but both are grayed out and can't be selected. This means I can't enter something like '(anon ClassifierRole):ClassName'. Stopping and restarting ArgoUML with this diagram didn't help.

This wasn't working this way last week; I could create ClassifierRoles and their Base classes using this technique without a problem. However, since then, I upgraded from Ubuntu 8.04 to 8.10, which I think involved an upgrade or repair to my Sun Java software. This seems to have changed a number of things in ArgoUML. For instance, printing now works. Previously, printing just hung ArgoUML on my system.

Thanks for your advice and suggestions. I hope to hear from someone shortly; my term project is due in two weeks!

-Kevin

Kevin Zembower
Internet Services Group manager
Center for Communication Programs
Bloomberg School of Public Health
Johns Hopkins University
111 Market Place, Suite 310
Baltimore, Maryland  21202
410-659-6139