Have you ever seen a Xerox Star? Perhaps you'll redirect your fanboi biases somewhere else when it's pointed out that the only difference between a Macintosh window and a Xerox Star window was the number of lines in the title bar.

Paying for it makes it legal for them to use but is irrelevant to the concept of a patent unless the documents say so. Regardless, it doesn't change the fact that they stole it, then tried to claim it as their own patentable idea and sue the bejesus out of every one else. And the Xerox lawsuit you claim? As I recall, they were on the verge of filing a "friend of the court" brief on Microsoft's side of the look and feel lawsuit, after which the lying thieves of Apple dropped their lawsuit. I.e. Xerox may have let them use the idea but did not grant them the exclusivity that Apple fraudulently tried to claim. Apple Corporation was and is built on unethical and dishonest behavior.

What's more bothersome is that fanbois like yourself don't care as long as you "win". Go team!