Fix the droptarget. RES-829

Author: michaeldemey

src/main/java/com/itextpdf/rups/Rups.java

@@ -109,9 +109,9 @@ static IRupsController initApplication(JFrame frame) {
         final RupsMenuBar rupsMenuBar = new RupsMenuBar(rupsController);
         rupsController.addObserver(rupsMenuBar);
 
-        frame.setDropTarget(new RupsDropTarget(rupsController));
         frame.setJMenuBar(rupsMenuBar);
 
+        frame.getContentPane().setDropTarget(new RupsDropTarget(rupsController));
         frame.getContentPane().add(rupsController.getMasterComponent(), BorderLayout.CENTER);
         frame.setVisible(true);