Solved: Show Annotations from Skim (Mac)

I am new to JabRef and want to use it on Windows as well as on Mac. The new feature to show PDF annotations in JabRef seems useful. Annotations made with PDF XChange Viewer on Windows are shown perfectly; however, I can’t get annotations with Skim, a popular PDF viewer on Mac, to be shown in JabRef.
I searched in vain for a list with PDF editors that are supported by this feature. Am I doing anything wrong or will Skim be supported later on?

Edit: Okay, as always, I had to post first to stumble across new information:
By default, Skim does not save the annotations in the file but separately, I had to “export” the PDF with included annotations and then JabRef was perfectly able to grab them.