What steps will reproduce the problem?
1. create a CSS selector such as div#main_content or h2.sub_heading
What is the expected output? What do you see instead?
highlighting for class or id only matches up to the underscore, leaves the
underscore as plain text node, and matches the rest of the class or id as a
keyword
What version of the product are you using? On what operating system?
Using r52 straight from SVN, Windows 7, PHP 5.2.9
Please provide any additional information below.