How does the scene between Portia and the Prince of Morocco further Portia's characterization

In Act II, Scene VII, Portia sends the Prince away in a way that reveals either her inability or refusal to always act in a way that reflects her name and position.

"A gentle riddance. Draw the curtains, go. / Let all of his complexion choose me so"

In these lines we see that Portia has a mind of her own..... that she is not prepared to play the dutiful daughter at all times. Portia has no interest in a man who does not reflect and compliment the way in which she has been raised.