Fix notifications that overlap task bar

src/main/java/org/jabref/gui/JabRefDialogService.java

@@ -339,6 +339,8 @@ public void notify(String message) {
             .text(message)
             .position(Pos.BOTTOM_CENTER)
             .hideAfter(TOAST_MESSAGE_DISPLAY_TIME)
+            .owner(mainWindow)
+            .threshold(5, Notifications.create().title(Localization.lang("Collapsed Notification")).text(message))
             .hideCloseButton()
             .show();
         });