A main window is the basic App Builder object. It is created by dropping a main window icon on the workspace. The starting point for a user interface is built in a main window. A main window has a minimize button and therefore can be iconified.
The status region includes the name of the module the window is part of and indicates when the window object is selected. It does not appear in the compiled application.
Examples of main windows used in building App Builder itself are the App Builder primary window, the Project Organizer, the Module Browser, and the Code Generator.