This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
Currently the only way (AFAIK), how to refresh DiffView (reread source files) is to create a new DiffView and replace old one. We appreciate it in Refactoring Preview UI. Please consider this request for 6.0 Thanks.
Diff view is automatically refreshed if StreamSource provides a FileObject or a Document.