User Assistance. This is helping the user with the proper "next step" when performing a task. Less guesswork for the user on what to do next makes for a better experience.

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

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.

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.

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.

Other examples of these animations might be to show the status of an FTP transfer, the progress of media being digitized, or an updated time signature. And don't forget that users may want to have some control over this, so give them plenty of options, including the ability to turn these functions off.

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

Drawers. Similar to Sheets, this is a "child" window that gives users access to items that do not always need to be present. But when do you use a drawer and when do you use a palette?

In building your amazing Aqua application, one of the most important things to consider is the Dock. There are three things your app needs to be "Dock Compliant." Now, I write this knowing that the Dock will be going through some major changes soon, but for the most part, these should still hold true.