A window that displays debugging information. It presents a list of the methods that were active when the error occurred. The developer can walk backwards through this list to investigate the problem.

In Dynamic Data Exchange, a request by a DDE client to a DDE server to be notified when an particular data item changes. The notification does not include the value of the changed data item. Contrast with hotlink, coldlink.

An object that provides a user-interface abstraction; for example, a scroll bar widget. Widgets support obtaining input from the user and displaying output to the user.

A pattern-matching character.

A rectangular area of the screen with visible boundaries in which information is displayed. Windows can overlap on the screen, giving the appearance of one window being on top of another.

In the Composition Editor, a part that can be used as a container for other visual parts, such as push buttons.