Environment: It should be run in as many supported browsers as possible. At least: Google Chrome 80. MS Edge 44 (EdgeHTML 18). Mozilla Firefox 74. Internet Explorer 11 Ghostscript. If it's not installed, you can execute the following commands from the console:  $ apt-get update $ apt-get install ghostscript Testing instructions: Login as admin. Access to "Site administration / Server / System paths", set " Path to ghostscript " to '/usr/bin/gs' or the corresponding to your environment and Save changes. Check  a green check is displayed near the "Path to ghostscript" field. Access to "Site administration / Plugins / Activity modules / Assignment / Feedback plugins / Annotate PDF" and check "Annotate PDF" feedback plugin is enabled. Create two students. Create a course. Create an assignment with Annotate PDF feedback ticked. Enrol a student (yourself) into the course. Login as the student and submit submission. Login as a teacher and grade submission. Add a multiline annotation comment. With the `comments` tool selected, attempt to highlight the text in the annotation comment with a mouse. Confirm , that it highlights the text rather than dragging around the assignment.