Lately several of us have been having problems when switching to preview mode for even a simple RUI handler that contains a dojo widget. If we click on that widget, RBD locks up and window saying "Java Platform SE binary has stopped working" displays. RBD exits and we see the attached eclipse dialog that starts with "Java was started but returned exit code = 255". I've seen other exit codes too, so it's not always 255.
This only happens in preview mode. If we display the same handler in an external browser it's fine. I've hunted around in my various Java preferences but have not found anything that makes a difference.
RBD 18.104.22.168 (also happens in 8.5.1)
Win 7 64bit
Any thoughts where else I should look?