diff --git a/grade/report/grader/styles.css b/grade/report/grader/styles.css
index a1159e2451d..53618731b9b 100644
--- a/grade/report/grader/styles.css
+++ b/grade/report/grader/styles.css
@@ -344,6 +344,7 @@ table#user-grades th.fixedcolumn {
     width: auto;
     clear: none;
     overflow-x: scroll;
+    overflow-y: hidden;
 }
 .path-grade-report-grader .left_scroller {
     float: left;