Classes can be hidden from view to simplify what's on display, scan specific class marks more quickly, and load the Markbook faster.
Students are grouped into their classes in the Markbook. Each class is labeled with a pale yellow header row.
Click on the + icon in the class' header row to reveal its students. Similarly, classes can be collapsed by clicking on the - icon.
Collapse the entire Markbook by clicking Collapse all in the upper left corner of the page.