I submitted my first XUL bug report today. Print Preview of an XUL menu will cause Mozilla 1.3 and Netscape 7.0 to crash. Bummer. That's one of the "features" we're building into our product.
Update: Apparently, this got marked as a duplicate. I did quite a bit of searching to ensure that I wasn't submitting a dup, but this bug manifests itself in various guises, depending on how one is using Print Preview.