Sorry, didn't read the question very well. Please accept my apologies.
The vertical line is difficult to see in 6 because it is black on dark blue since the question slide is always selected.
Another way to speed up after the second step of submitting, is to change the actions On Success/After Last Attempt from 'Continue' to 'Go to Next Slide'.
I blogged about such tweaking solutions:
http://blog.lilybiri.com/question-question-slides-in-captivate
http://blog.lilybiri.com/question-question-slides-part-2
Lilybiri