For example, if you see an AIM window peeking out from behind your browser and you click on it, that window will come to the front, but the main application window will not. The Mail.app/Activity Viewer is another example. The Aqua system of layers works well in many instances, but not in all. Thank goodness that the Dock is always there to come to the rescue. I know that clicking on an application icon in the Dock will always result in not only the application coming to the front, but also any non-minimized windows associated with it. And if the application is active but no windows are open, clicking on the Dock icon should create a new window in that application.

Okay, I just told you what Apple wants you to look out for with window positions, but in the real world, not everyone uses the hiding feature of the Dock, and it is unrealistic to be able to predict where each user will place their Dock at any given day or how large they will have it. However, you can build a feature into your application that allows spacing for the Finder. You can give users the option of where to position their windows and what area of the screen not to cross. I know that BBEdit provides me with this feature, and I wish more developers gave me more control over my windows.

Due to the positioning of the Dock, remember that when you build an application, you have to be sure that new document window sizes and positions do not violate the Dock's space. Dock is temperamental and Dock loves his space. If you default to a window size that expands behind the dock, users will have a difficult time reaching the navigation and resize areas at the bottom of the screen. I can personally say that more than once I have been rather peeved that I couldn't get to an area of the window to resize because the default window settings always pop up behind the Dock. In addition, the new Dock in 10.1 will allow users to position their Dock location on either side of the screen as well.

Dock Animation. Sometimes animating icons in the dock can be useful in communicating the status of the system or application.

If an application is designed well, the reward for users is that they will learn it faster, accomplish their daily tasks more easily, and have fewer questions for the help desk. As a developer of a well-designed application, your returns on that investment are more upgrade revenue, reduced tech support, better reviews, less documentation, and higher customer satisfaction. The rewards of building a good-looking Aqua application are worth taking the extra time.

Adhere to Window Models. Document windows, Utility windows, Click-through, Layering, Drawers, Controls. How do users open windows, how do you properly title windows?

Adopt Sheets. I really like the use of Sheets in OS X. The use of Sheets lets me know which window my dialogue belongs to without hijacking my system.

Adhere to System Appearance. Does your application use all the sweetly colored buttons, delightfully shaded windows, and all the other "bells and whistles?"

Help! Did you include help tags in your applications? (I'd be lost without them.) Also, be sure to take extra time to develop your other help files. The Apple Help Viewer supports HTML, QuickTime, and also AppleScript. Take advantage of it! There isn't anything I hate more than going to the Help menu and finding there isn't any help.