Xerox sued, but the case was dismissed without addressing the claims, because it was filed as the wrong type of case, in the wrong court.

http://www.nytimes.com/1990/03/24/business/most-of-xerox-s-s...

Xerox did give Apple access to PARC, but see how that allows Apple to freely use any of their IP without compensation.

According to Xerox:

''The ruling does not mean Apple hasn't taken substantial portions of the Star and claimed them as their own,'' a statement issued by Xerox said. ''The court merely held, we believe erroneously, that Xerox does not have standing to present facts in support of our contention.''