When grading an assignment submission using PDF Annotation on a Mac, if a user does not have their browser screen maximized, the annotation options (such as sticky note, highlight, pen, etc.) disappear. This has caused some instructors to think that the grading feature is broken as there is no indicator that the items have been hidden. I'd like to see a scroll option as in PC or some kind of indicator of "see more" or "expand menu" so that folks know the options have been hidden and are not just missing.
We are currently on 3.9- while we don't recall this issue on the 3.6 version we upgraded from it's also possible that with more folks working from home on laptops the issue simply wasn't noticed.
We have observed the behavior in Chrome, Safari, and Firefox.
Scroll the pane containing the annotation controls and you'll see them below the page navigation controls.