Troubleshooting Vergil

How do I start Vergil by hand?
See How do I invoke Ptolemy II?
The user interface appears to be frozen, but windows are redrawn.
A modal dialog may be open. Unfortunately, these dialogs do not appear in the task bar on windows systems, so the only way to find them is to put windows in the background until they appear. You can do this by repeatedly hitting Alt-Escape.
My model hangs, failing to make progress.
In the DE domain, if an actor has input tokens that it fails to consume when it is fired, then it the director will continue to fire it repeatedly until those tokens are consumed. Actors in the DE domain must consume pending input tokens.
Ptolemy seems to consume more and more memory after opening and closing several demos.
The drag and drop mechanism has contained many memory leaks in older versions of Sun's JDK. The leak occurs because there are references internal to the platform drag and drop system that do not allow windows using drag and drop to be properly garbage collected after they are no longer visible. If you run into problems, we strongly suggest upgrading to the newest version of Java. We have seen memory leaks of this sort in versions of Java prior to 1.3.1 beta.