After a grading policy is in place, learners can view both their problem scores and the percent completed and current grade in the Progress tab for the course.
Each item in the X axis of the chart is for a graded subsection. Graded problems in units are not broken out in the chart; the score from each problem in the subsection is added to that vertical bar.
Graded subsections are grouped in the chart by assignment type rather than listed in chronological order. For example, all homework exercises are grouped together, followed by labs, then exams.
The x for an assignment in the Progress tab indicates that the grade for that assignment is currently dropped. You configure how many assignments are dropped when you configure assignment types.