Reviewers: bobv, Description: Fixes http://code.google.com/p/google-web-toolkit/issues/detail?id=5375, calling setDisplay(null) from a PlaceChangeEvent.Handler will cause an NPE in the ActivityManager's own PlaceChangeEvent.Handler
Also undoes demo-time hack that left stopped widgets in place to reduce flicker. Apps will have to reduce flicker themselves. Please review this at http://gwt-code-reviews.appspot.com/988801/show Affected files: M user/src/com/google/gwt/activity/shared/ActivityManager.java M user/src/com/google/gwt/activity/shared/ActivityMapper.java M user/test/com/google/gwt/activity/shared/ActivityManagerTest.java -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
