I'd like to suggest additional highlighting entries for:

Operators: &&, ||, !=, etc
Evaluation brackets: [ ]
Parenthesis: ( )
Block brackets: { }
Numbers
Event prefixes: ^, *, &, !, me:
Identifier parameter separators: ,
Properties
Dialog controls: button, text, etc

Also, the 'identifier prefixes' option doesn't seem to work unless I'm misunderstanding it.

I thought the "!" in $!time would be treated as a prefix but it's not. If this is supposed to be what it's for and it needs a fix, then you might as well support . and ~ as prefixes too.