Thanks, keibun! Your description is very helpful. I have created an issue in JIRA: https://jira.jboss.org/jira/browse/JBIDE-5236 Here is my comment as to what is the cause of the issue: Initially there is null pointer exception in method resolveInternal() of class StrutsProcessHelper, because it treated comment objects in the same way as action objects, which was not correct. The exception was caught by method runTasks() to be logged, but because inconsistency in MANIFEST.MF, instance of log was not initialized, so that another null pointer happens, and having left uncaught, interrupts the update of diagram. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4266759#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...