Is there a way to configure oXygen to visually indicate which elements in an XML instance document are schema-optional?

Hi Folks,

I was given a large XML instance document that conforms to an XML Schema.

I am viewing the instance document using oXygen XML.

Is there a way to configure oXygen so that it visually indicates which elements in the instance document are optional -- perhaps displaying the elements in red color or some such thing?

/Roger