HyperCard 2.0 provides ways for XCMDs to create and manage their own windows and menus and to call the Sound Manager directly.
A window that is managed by an XCMD is called an EXTERNAL WINDOW. With external windows, HyperCard 2.0 can support color pictures, custom palettes, custom text editors, fast terminal emulators...just about anything you can imagine.
HyperCard 2.0 contains several built-in XCMDs that manage external windows, including HyperCard’s script editor and debugging tools.