Sublime Text is an awesome text editor for code!. This is a powerful alternative to Notepad++, with a really slick UI.
If you’re on Mac or Linux, no problem the program will work by default. However, if you’re on windows (which I presume the majority of readers are) it requires a small tweak to make it use APL font.
1:Once you have installed the program navigate to the Preferences – Settings user
2. You will be pressented with the user config. Enter these lines between the curly braces.
“font_face”: “APL385 Unicode”,
“font_size”: 10
3. Congratulations you are ready to go! APL text is now correctly displayed!
Below is the websites description of the licencing of the software. So you can try it out for free! Check out and tell me what you think in the comments!
”Sublime Text 2 may be downloaded and evaluated for free, however a license must be purchased for continued use. There is currently no enforced time limit for the evaluation.”
Here’s a list of the supported languages it can highlight syntax for. C, C++, C#, CSS, D, Dylan, Erlang, HTML, Groovy, Haskell, Java, JavaScript, LaTeX, Lisp, Lua, Markdown, MATLAB, OCaml, Perl, PHP, Python, R, Ruby, SQL, TCL, Textile and XML.
Further languages can be added via add ons but I have had no luck finding a add on for APL.
Three Blind Mice 
I wrote one around a year after you made this post.
https://github.com/StoneCypher/sublime-apl
Wow, that is fantastic! would you mind if I made a blog post linking to this?
I just tried it out and its excellent!