Inline substituion for resource strings

I'm missing something obvious but as a newbie to Intellij I'm kind of like a rabbit in the headlights with so many great options.

Somehow the code editor replaced some Java call for fetchnig resource string values with the actual strings (hiliting the string text black in zenburn theme). e.g

Log.d("ASYNC", c.getString(R.string.eoa));

read as

Log.d("ASYNC", "End of Asynchronous Call"); //<--- string text was black

What's this functionality called in the editor formatter and how do I use/turn it off?

thanks

r.