In the "Edit Details" window for a bib-entry, there are some oddities with removing fields. I wasn't able to find another post on this, so pardon me if this has already been pointed out.
I have an entry that has a "Language" field. That's not that important to me, so I click "Additional fields...", scroll to "Language", un-check it, then go back to the window. Now the field is gone. I hit "Save" and open the "Edit Details" window for the entry again and the "Language" field has now been inserted again. The same happens if I use the "Save and Next >" button.
Now I try again, but this time I open "Additional fields...", scroll to "Language", and this time hit the "i" icon to the right. When I go back to the window, the "Language" field has been cleared but not deleted. Nevertheless, I click "Save." I open the "Edit Details" window again, and now the "Language" field is gone.
Thus, the check-box and "i" icon seem to be mixed-up in their functionality when removing fields. Adding fields seems to work just fine.
Paperpile is a great program! I'm very impressed with its functionality. Thank you for working on this. It will help me greatly in writing papers in my semesters to come.