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.

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.

But limit your animations to whatever is required to communicate the necessary information. Avoid annoying animations that discourage ease of use. Ask yourself, "What do I need to show the user, and what is the cleanest way possible to achieve that?" A good example is the Mail application for Mac OS X. Whenever a new message arrives, the Dock icon changes appearance to indicate a changed state.

To put my money where my mouth is, in each new article I'll build a hypothetical application that illustrates the guidelines I'm covering. Today's application is called "Paint" and will be based on the photo-illustrative icon I created in my last article. Together we will complete each step, and by the end of the project we should have a well-designed, 95%-100% Aqua-compliant application. I'll leave some room for personal preferences and the fact that Apple changes the OS every few months.

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.

To put my money where my mouth is, in each new article I'll build a hypothetical application that illustrates the guidelines I'm covering. Today's application is called "Paint" and will be based on the photo-illustrative icon I created in my last article. Together we will complete each step, and by the end of the project we should have a well-designed, 95%-100% Aqua-compliant application. I'll leave some room for personal preferences and the fact that Apple changes the OS every few months.

This topic is one we will tackle later in this article, but it refers to making sure that your application and the dock aren't fighting it out for supremacy of the screen.

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.