There are a variety of ways in which an application can display text, accept text input or allow editing of text by the user. Display panes show non-editable text, text input panes are used for entering short pieces of text, and editor panes are commonly used for dealing with large amounts of text such as files. Rich text panes are available on Cocoa and Windows, supporting formatted text.
CAPI User Guide (Macintosh version) - 30 Aug 2011