I noticed that although I had 35 students in a course the user select box in gradebook user report only had 34 users.
To see this issue simply browse to any course with at least one student, take note of the number of students and then view the user report for that course.
You will notice that there is one less student shown in the drop down in the top right than there are actual students.
This issue seems to have popped up only in HEAD as the line that causes the problem isn't in 19.
I have attached a patch that I believe fixes this very minor bug if somebody could please review this for me that would be most appreciated.