Hi Rolf,
The first part of your post sounds like a bug. However, I am not able to repro it. (The IDE does not disappear when I try to rename an identifier in my project.)
Can you please report the bug at our Ladybug Product Feedback Center?:
http://lab.msdn.microsoft.com/productfeedback/. Please include whatever info you can about your project and the specific repro steps.
I'm glad to hear that you've installed Refactor!. This Rename option is not available in Beta2, but will be in the final product. So, you can look forward to seeing it then.
Thanks,
Lisa Feigenbaum
Visual Basic Program Manager