Textedit

The underlying text engine was the TextEdit Manager built into Mac OS. TextEdit had originally been written to support very small runs of editable text, like those found in Save as..

TextEdit currently (as of July 2009) has limited ability to edit RTF document margins.

The high-resolution TextEdit 1.5 icon found in Mac OS X versions starting with 10.5 (Leopard) features an extract from Apple's " Think Different " ad campaign.

This is in contrast to the TextEdit APIs found in the earlier Mac OS. When extensions are needed, Cocoa's use of Objective-C makes this a straightforward task.