Steven, The issue seems to be that there is no way of instructing GWT which jars are even relevant to GWT. My project is fairly large and depends on a large set of server-side libraries that are on the classpath, but will never change on a refresh, and even if they were to change, would not impact GWT. Perhaps this is something that could be addressed in tandem with the GPE, and then it could be smart enough to only look for changes for classpath entries that are part of open projects.
Can any googlers add some wisdom to this thread? -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
