Tinn-R is free, simple but efficient replacement for the basic code editor provided by Rgui.
Tinn stands for the recursive acronym ‘Tinn is not Notepad’. It is initially written as a small ASCII file editor primarily intended as a better replacement for the default Notepad.exe program distributed with Windows. With versions, it grew to a fairly complete, yet simple and compact code editor.
Tinn is written in Delphi 5 and it runs only under Windows (9X/Me/2000/XP). It is free and distributed under GPL 2.
Download: Tinn-R 2.3.2.2