Add a draggable control to Moodle’s grader so you can fine-tune the split between the review panel and the grade panel, remember the split across students, and keep Moodle’s native layout/animations.
Moodle Grader Toolbar Split Slider adds a small slider to the grader’s layout controls on assignment pages. In split view you can fine-tune how much space the review panel and the grade panel take. The add-on remembers your preferred split as you move between students.