Canvas supports automatic grading periods — that is, assignments are automatically sorted into their proper window based on their due date.
Aside: In fact, if you use differentiated assignments and an assignment is due in one window for one student and in another window for another student, I believe that Canvas is sharp enough to calculate each student’s grade based on their due dates.
That said, it can be disconcerting, as the window changes, to see vast swathes of assignments disappear (or appear). As teachers, we can change which window (or grading period) we are viewing in the Gradebook using the drop-down menu above our list of students:
What does the Total column reflect?
The total column reflects the total grade for the currently selected grading period. That is, if you are looking at “Window 1,” then then Total that you see is calculated for Window 1. Alternatively, if you are looking at “All Grading Periods,” then the total you see is calculated for the entire year.
The assignment group averages (if you use assignment groups) are similarly calculated based on the visible assignments (i.e. the selected grading period) and, if you weight assignment groups, that weighting is factored into the total grade for the visible grading period/assignments.