DECORATE parser was written by CodeImp, from what I know. And all that clusterf**k is his heritage.
And I kind of can understand that actually, as, like Major Cooke pointed out, no one expected that actors would be defined with anything else than DECORATE.
And no one would expect that someone is going to write 20 more parsers based on the DECORATE one either (GZDB currently parses almost all text formats, except TEXTURES and maybe something else).
Anyway: enabled $-comments (//$Category, etc, all that are currently supported for DECORATE).
Not sure where these were supported in DECORATE, but in ZScript they will only be picked up if you put them in Default{} block.