I am also having the exact same same problem as DrunkenCyclist. It is intermittent, but driving me crazy. If I click on another note then back onto the note with the .jpg I am trying to annotate, it sometimes works.
I also cannot delete two notebooks that were shared with me. I have tried all of the above suggestions. I have emptied all the notes out of the notebook. When I right click and click 'Remove Notebook'. The dialogue box appears as shown in the attached screenshot, I click Delete and nothing happens Im Running on a MacBook Pro