Depending on whether or not you're now subject to the "New GMail Format" as of October 29th, 2007 - this will clean up the underlining in the left side boxes (Compose and Labels window). One of my 3 GMail(s) is on the new format, currently with an option to use "older version."

PLEASE NOTE that the red bold "Compose Mail" and "Contacts" labels are the result of one of my other styles.

I REALLY like this new version of GMail - and the added space - but got used to having no underlines. I'm reworking some of my other GMail scripts as time permits - most problematic will be the "colored buttons" style. Right now it's a "default all green," but hopefully we'll get some variations soon.