Learn@UW/D2L - Possible Problem Grading using Student Link in Course with Large Gradebook
If you have a course with a fairly large gradebook (for example over 50 grade items and 100 students), clicking a student's link to enter or edit the student's grade may lead to difficulties, especially, if you are using Internet Explorer.
With Internet Explorer, you may get a popup stating your site is not
responding to a long-running script. After closing this popup, when you
enter some grades, edit some grades, or erase some grades and then press
the Save button, the process may hang.
With other supported browsers, such as the latest version of Firefox or Chrome, the operation will usually succeed. However, you may find the process is sluggish.
This is a known issue expected to be corrected in the near future.
Until the issue is corrected, if your course has a large gradebook, edit grades from the 'Edit Grades' screen instead of using student links or use a supported browser other than Internet Explorer.