Multiline Text Editor

Text Widget Overview — Overview of GtkTextBuffer, GtkTextView, and friends
GtkTextIter — Text buffer iterator
GtkTextMark — A position in the buffer preserved across buffer modifications
GtkTextBuffer — Stores attributed text for display in a GtkTextView
GtkTextTag — A tag that can be applied to text in a GtkTextBuffer
GtkTextTagTable — Collection of tags that can be used together
GtkTextView — Widget that displays a GtkTextBuffer