From iA wiki
See also: Editors
NoteTab can handle enormous file sizes, is customizable, and extremely easy to use. As its name suggests, it works extensively with tabs, which can be arranged in various ways and are clickable. Several panels can be shown or hidden: a file/directory explorer, a "clipbook" (a collection of easily programmable macros), a document outline etc. The editor itself has all the usual features, including regular expressions, spellchecking, thesaurus and syntax highlighting. Files are loaded very fast, and it's possible to search and replace in multiple files (including closed ones). The editor comes with a large collection of "clips" (macros) for all kinds of purposes, ranging from HTML wizards to interactive unit conversion. Many more are available on the web.