It would be great if the user may select in the preferences that he wants the annotations to be saved into the original pdf by default.
I know that you can save the annotations via the "Save as..." option, which is great. However, if you forget to do so, the annotations are just local.
I also think there should be a checkbox for this in the Annotations settings. In fact, I want this so bad that I'm considering to add it myself. I have no experience with KDE development, however, so I'll look into it more in August, when my exams are finished.
Probably duplicate of https://bugs.kde.org/show_bug.cgi?id=315552 or of one of the two bugs referenced into https://bugs.kde.org/show_bug.cgi?id=315552#c5
Thanks, Luigi. For me it would be solved when that issue is solved. Saving them by default would be of my preference too.
*** This bug has been marked as a duplicate of bug 315552 ***