If JabRef has do display several messages very shortly after each other, the messages are stacked and played one after each other. This is confusing, since the SnackBar is still displaying a message, which is already obsolete. E.g. if you cycle quickly through the preview styles.

A simple solution would be to stack the messages inside an already showing SnackBar, separated by a new line and to lengthen the display time of the SnackBar for the time only the last message should show.