[Plot Annotations Follow up]

[unlikelyzero]

Follow up from #5853 (comment)
Verified partially fixed Testathon 2023-02-06: all items in testing instructions verified, except step 2. While in real-time mode and unpaused, alt-shift initially zooms the view and then allows point selection, but not only now that the plot is paused. This is very inconsistent gesturally for the user; what should be be done instead is this:

On mousedown, detect alt-shift being pressed.
Immediately pause the view, orange border, etc., AND suppress zooming, allowing point selection to happen immediately.
The user will then manually have to unpause the plot when they've completed annotating; this is fine.