[ReignOfError]

The fact that Xerox has not tried to sue Apple is the clearest indication that the GUI concept wasn't technically stolen. But that doesn't change the fact that idea wasn't Apple's (could not be copyrighted by Apple) and therefore couldn't be stolen from Apple by Microsoft, as alleged in Apple's lawsuit.

Ideas cannot be copyrighted. Specific design elements and implementations can be patented (though "look and feel" patents are controversial), and those elements were introduced on the Mac, duplicated in Windows, and absent on the Alto/Star.

[The_Victor]

Ideas cannot be copyrighted. Specific design elements and implementations can be patented (though "look and feel" patents are controversial), and those elements were introduced on the Mac, duplicated in Windows, and absent on the Alto/Star.

If I understand the legal outcomes correctly, the "ideas cannot be copyrighted" concept was in fact a landmark of Apple vs Microsoft.