The chapter presents specifications and recommendations about the appearance and behavior of these windows, including how the window frame should look, how the user interacts with windows, how you should display them on the screen, and how they interact with each other.
Windows provide a way for people to view and interact with their data.
Windows have standard appearances that create a sense of perceived stability for people because they have a standard way to view and interact with all the different kinds of data they can create and store on Macintosh computers. The application puts one or more windows on the screen, each window showing a view of a document or of auxiliary information used in processing the document. Generally there is only one window per document. Multiple windows for the same document can confuse the relationship of windows to icons. You can provide multiple views to a document by implementing the capability to split windows or by adding utility windows.