OSX 10.7, Adobe Illustrator CS 5.1
When you save a PDF in AI, it automatically opens in Apple Preview (or whatever PDF application you have set as default). So, if you're editing several PDFs, and you like to save often (which is wise), your work is continually interrupted by application focus shifting to Preview. Aggravating to no end.
I've searched high and low for an answer to this seemingly trivial issue; it's not in Preferences, and I can't find anything on help sites or the broader Web.
I'm trying to keep Illustrator from opening a PDF at all when it saves, not just trying to change the default PDF application for my machine.