07-30-2011, 04:25 PM
Fine. I linked to it, and now I will simply copy the relevant section:
Closing Windows
Users can close windows by choosing Close from the File menu, pressing Command-W, or clicking the close button. Follow the guidelines in this section to ensure that your app closes windows as users expect.
Use modern APIs to preserve the window’s state. Regardless of whether you support Resume, you should remember a window’s onscreen size and position so that you can restore the user’s state when they reopen the window (or reopen your app). To learn more about how to use modern APIs to do this, see “User Interface Preservation” in Mac OS X Application Programming Guide.
In general, quit when users close the last open window in your app. In apps that are not document-based, users generally expect the app to quit when they close the main window. If an app continues to perform some function when the main window is closed, it might be appropriate to leave it running after the user closes the main window. For example, iTunes continues to play after the user closes the main window. If users close the last remaining document window in a document-based app and switch to another app, it’s appropriate to quit the app.
Display a close confirmation save dialog when users close a document window that contains unsaved data. Note that this behavior is automatic in document-based apps that adopt Auto Save. The close confirmation save dialog is similar to the standard Save dialog, but it adds a message that asks the user if they want to save their work. The reason for the message is that the action of closing the window implies that the user wants to discard their changes; if this is not the case, the user can respond by saving the data or canceling the close. Note that the close confirmation save dialog is not displayed if the document window closes as the result of some other action, such as the user quitting the app. In these other situations, you should automatically save the user’s work so that the user can choose to save or discard it at a later time.
After a document has been saved the first time, the close confirmation save dialog is not displayed when users close the document window, because users expect their changes to be saved continuously and without their intervention. (For learn more about save dialogs, see “Save Dialogs.”)