Setup Create a course with 3 students (s1, s2) and a teacher (t1) Make sure "unoconv" document converter is installed and enabled (and working). Create an assignment with the following settings: Submission types Online text Feedback types Annotate PDF Require students to click the submit button Yes Attempts reopened Manually Log in as each user and create an online text submission. Make sure that each submission's text is unique from one another. Switching users on the grading page Edit  mod/assign/feedback/editpdf/ajax.php and add "sleep(10);" at the top of the file (second line). Log in as a teacher Grade the first student, while the grading page says "Generating the PDF", click the arrow on the top right to change to the second student. Verify the PDF for the second student is shown (after the 10 second wait). Viewing annotated PDFs Revert the changes that you made on the previous section. git reset --hard Reload the grading page. Grade s1 and s2's submissions. On the PDF annotation tool, scribble the user's name/username of the submission that you are grading. Go to "View all submissions" table. Click on the "View annotated PDF..." link for each student. Verify the correct feedback document is shown for each student.  Viewing annotated PDFs for multiple attempts On the assignment grading table, click on Edit for s1's submission, then select " Allow another attempt " On another browser session (e.g. incognito window), log in as s1. Create another submission. Back on t1's browser, grade and annotate s1's new submission. Go back to s1's browser window. Refresh s1's browser window. Click " View annotated PDF... " under the Feedback section Confirm that you can see the annotations made by t1 for s1's latest attempt. Click " View annotated PDF... " under the Previous attempts section Confirm that you can see the annotations made by t1 for s1's first attempt.