I think there is a bug into some themes with PHP,

it doesn't color what it is in braces into a double-quotes string (Complex (curly) syntax) 

Here are exemples :

With Espresso Libre theme

Brackets should be in brown not green.

With Cobalt theme

db should be in white not yellow, but at least braces and brackets are in light

Do you have the same issue?

Cheers,

Ronan