Komodo Edit

Komodo IDE is a development environment for programming in dynamic programming languages. Komodo Edit is a sister software designed exclusively for writing code and can be downloaded for free, no matter what suite it comes from.

It includes basic features – such as autocomplete, syntax check, and highlighting – and other useful features such as code thumbnail previews to help you quickly browse through a lot of code. You can also customize tabs and windows on the interface. Komodo Edit was designed for dynamic languages like PHP, Ruby, Perl, Python, and TLC, though it also lets you work with XML, HTML, Javascript, and CSS.

The program uses calltips, which are drop-down menus that let you select attributes for different code tags. Komodo Edit also has the same extension system as Firefox.