Can't view and edit contents of highlight annotations after document is reopened
To reproduce, highlight some text, save, close and reopen the pdf. Left- or right-click on the annotation in the text and you'll see that neither a note can be added to the annotation, nor the annotation can be deleted from the context menu. In order to do so, you have to use the annotation sidebar. But even there you can't add a note to an existing annotation.
Observed under Ubuntu 18.10 with 3.30.1.