The case of Apple Computer v. Microsoft has been in the courts for many years. Many of the issues involved, turn on the terms of a license agreement granted by Apple to Microsoft in the early days of personal computing and will not be considered here. Some of the other issues involved go to the general question of what degree of protection should be afforded by copyright for computer software. Central to this case were a number of visual displays occurring in various WINDOWS programs in particular relating to the way in which various features are overlaid one upon the other on a monitor of a computer using WINDOWS software. The license agreement between Apple and Microsoft was found by the Ninth Circuit Court of Appeals to cover 90% of the alleged copying in two of the WINDOWS programs involved and two-thirds of the features of a third program involved. The Court found that under these circumstances "and the limited number of ways that the basic ideas of the Apple graphical user interface (GUI) can be expressed differently", that "only thin protection, against virtually identical copying is appropriate." In the case before it the Court held that the appropriate way to determine whether the unlicensed elements of Microsoft's programs constitute copyright infringement involved a three-step analysis: first, to identify the alleged similarities between the plaintiff's work and the defendant's; second, to determine whether the allegedly similar features were protected by copyright by separating unprotectible ideas from protectible expressions of those ideas; and finally, to determine whether the plaintiff was entitled to broad or thin protection in respect of features that were protectible. The Court felt that this was simply an alternative way of expressing the more familiar "abstraction-filtration-comparison" tests that had been used by other circuit courts. It is not entirely clear, however, that this is true.

The Court felt that the key issue in this analysis was closely related to the tradition of the scenes a faire doctrine that had evolved in other areas of copyright. The Court noted previous decisions that held when similar features in a video game are as a "practical matter indispensable or at least standard in the treatment of a given [idea]" they are treated like ideas and therefore not protected by copyright. Thus, the Court concluded that a mere indispensable expression of ideas based on technical requirements may be protected only against virtually identical copying. Apple argued that the scenes a faire doctrine should not be used to limit the scope of protection in audio-visual copyright because GUI's are of a nature that their functional purpose should not outweigh their artistry. Thus the Court should look at the "total concept and feel" of the works in question to see whether they were substantially similar. The Court did not agree and held that the party claiming infringement could not place reliance on any similarity and expression that resulted from unprotectible elements. The Court, however, found that almost all similarities in the present case sprang either from the license or from basic ideas and their obvious expression and so it concluded that unlawful copying could only occur if the works as a whole are virtually identical.

Although the particular facts of this case make it a difficult one from which to draw general conclusions, the case does show a continuing trend towards narrowing of the scope of protection provided for computer software by way of copyright in the United States.