On this occasion, it wasn't my theoretical code that theoretically threw my syntax highlighter into a spin. Theoretically:) And I'm not going to be the one to risk Abigail-II's wroth by suggesting that $" should never be used!

In reality, the only time $" ever appears in my code, it is always localised, always on a line on its own, and always followed by a comment eg.

local $" = ', '; #"

The " in the comment serving to pair the first for the syntax highlighter.