Scrivener has some new writing tools, the first of which lets you focus your attention on specific parts of speech. It’s called Dialogue Focus (called Linguistic Focus in version 3.0.0 and changed in 3.0.1), and it's set up to help you view dialog separately from the narrative.
To use it, click in the text you’d like to analyze, and go to Edit>Writing Tools>Dialogue Focus. Then choose Direct Speech. NOTE: Direct speech means dialogue (or any text in single or double quotes).
Use the Fade bar to decide how visible the remaining text is.
To turn it off, select None, or close the Dialogue Focus window.