Re: It's the data harvesting
"So when Apple were running away with PARC's windows, icons, menus and pointing device ideas, they became completely unavailable to the researchers any more because they weren't copies. How does that work? Curious minds and all that."
Firstly Xerox were actually paid for Apple seeing and making use of the ideas from PARC. Secondly Apple didn't claim ownership of the Xerox ideas. What they claimed were the ideas they had come up with themselves in the approximately 5 years between them seeing the PARC system and the Macintosh. Things like repainting uncovered portions of windows automatically.
See http://www.catb.org/esr/writings/taouu/html/ch02s05.html for some of the history.