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

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

Not quite as entertaining as Shrek, but Dock animation can be an important and useful function in your application. For example, Dock animation is a helpful way to indicate the status of your application.

At WWDC, I listened to Apple representatives make some excellent points about taking the time to build a 100%-compliant Aqua application, and I think all developers need to look beyond the code and listen to what the folks at Apple have to say

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.

For my Paint application, I created a series of icons to simulate a rendering algorithm. While the application is performing this CPU-intensive task, you can always see the status of the document by the icon changing in the Dock.

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

So far in these articles, I have only dipped a toe or two into Aqua's pool. I have covered basic aspects of building an Aqua-compliant application, including the building of photo-illustrative/3D application icons. Now it's time to address other components of our Mac OS X 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.

Adhere to File Locations. Make sure that when your users save documents, your application knows where to put them and also gives users flexibility.