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?

Adhere to Layout Guidelines. Did you leave 12 pixels between your push buttons? Does the positioning of your pop-up menus make sense, and when do you use a pop-up versus a scrolling list? Are you using the right types of buttons for the proper functions?

Clicking an application in the dock should always bring forward an active window. If the user clicks on an open app's icon in the Dock, the application is active and all unminimized windows come along with it. I have found a few problems with windows behaving independently of their application.

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.

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.

By building an application that takes advantage of Aqua's many facets, you help ensure that your application will not only look good, but have a chance of becoming a raging success. After a new user clicks on the icon of your program, the first thing he or she sees is the application interface. I know that when I review a product, I am very critical of its visual design. I usually have a short time to learn the new software, so design and ease of use are very important. Aside from those who marvel at the beauty of the command line, most users tend to react the same way.

By building an application that takes advantage of Aqua's many facets, you help ensure that your application will not only look good, but have a chance of becoming a raging success. After a new user clicks on the icon of your program, the first thing he or she sees is the application interface. I know that when I review a product, I am very critical of its visual design. I usually have a short time to learn the new software, so design and ease of use are very important. Aside from those who marvel at the beauty of the command line, most users tend to react the same way.

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

Whether native or not, this is obviously one of the first steps on your way to OS X. Keep in mind that often, the functionality of your code has a lot to do with how your interface is designed. How many developers have come up with great functional ideas from working with their interface or looking at their competitors'? Start working on your Aqua compliance from day one. Don't wait until the last minute.