Why did Tiana assume Naveen was marrying Charlotte?
At the Mardis Gras parade, Tiana sees "Naveen" and Charlotte about to marry on the float. Ray has just told Tiana that Naveen has decided he will marry her instead of Charlotte and help her get her restaurant another way, etc etc. But as soon as Tiana sees this wedding happening she gets upset and runs away. It all sounds fair enough except:
Earlier in the movie Tiana saw Charlotte dancing with "Naveen" at the masquerade ball, and actually says to Naveen "If you're the prince who is Lottie dancing with?" (or words to that effect. She knows there is a look-a-like who was cosying up to Charlotte at the party, who Charlotte thought was a prince. So it would be safe to assume that she wasn't going to just let him go because she wants to be a princess.
Basically my long-winded post is just asking this: why, when Tiana was aware that there was someone getting loved up with Lottie who looked like Prince Naveen, did she automatically assume the wedding was for Lottie and Naveen rather than the look-a-like? Am I missing something? This is bugging me because it seems to be overlooking an important part of the movie just for dramatic effect, and it's not even subtle!