I've spent the past two hours trying to turn the Northwestern Webmail Enhancer into a Firefox extension, and so far I've had mixed results. First I'd like to say that the Greasemonkey Compiler is a fantastic tool, and has greatly simplified my work. However, I've run into two problems:
Directory integration no longer works because two Greasemonkey convenience functions (GM_setValue and GM_getValue) are no longer available. I'm going to have to do some reading on how to save extension settings.
There are some really odd things going on with the message index rendering now. I absolutely can't account for the problem. It works as a Greasemonkey script. It doesn't work as an extension.
I'm really wanting to avoid feature regressions, so it may be a while before I add new features. I think my immediate concern is to get the current feature set working.