The Arduino library tutorial says:
Classes should be KEYWORD1 and are colored orange; functions should be KEYWORD2 and will be brown.
On the Mac, there's no difference in color for classes and functions. They're both #cc6600, which is kind of half-way between orange and brown.
The keyword.txt file correctly tags the class with KEYWORD1 and the functions with KEYWORD2. Is the absence of a color difference a bug?