"Retry" should not remove the correct answers
In "fill in the blanks", when you click on "retry" all the answers are removed so the student will have to retype the blanks he had already filled in correctly.
A text with 10 blanks.
The student answers all of them.
He/She then clicks on "check".
He'll see that he/she has got 7 of them right.
The student then clicks on retry.
All his/her answers are removed including all the correct ones.
The student now had to retype all the 7 correct answers together with the 3 incorrect ones he/she was intended to correct.
This is not logical. It's counterproductive. It's a waste of time and takes the students' focus away.