public void mouseEntered(MouseEvent evt) {
   if (list != null) {
     TransferHandler th1 = getFileChooser().getTransferHandler();
     TransferHandler th2 = list.getTransferHandler();
     if (th1 != th2) {
       list.setTransferHandler(th1);
     }
     if (getFileChooser().getDragEnabled() != list.getDragEnabled()) {
       list.setDragEnabled(getFileChooser().getDragEnabled());
     }
   }
 }
    public ExampleField(ExampleOption option) {
      super(option);

      model = new DefaultListModel();
      model.addListDataListener(
          new ListDataListener() {
            @Override
            public void intervalAdded(ListDataEvent e) {
              fireChangeEvent();
            }

            @Override
            public void intervalRemoved(ListDataEvent e) {
              fireChangeEvent();
            }

            @Override
            public void contentsChanged(ListDataEvent e) {
              fireChangeEvent();
            }
          });

      final JList list =
          new JList(model) {
            @Override
            public Dimension getPreferredScrollableViewportSize() {
              return new Dimension(3 * CELL_SIZE, 2 * CELL_SIZE);
            }
          };
      list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
      list.setVisibleRowCount(0);
      list.setFixedCellHeight(CELL_SIZE);
      list.setFixedCellWidth(CELL_SIZE);
      list.setTransferHandler(
          new URIImportTransferHandler() {
            @Override
            public boolean canImport(TransferSupport support) {
              support.setShowDropLocation(false);
              return super.canImport(support);
            }

            @Override
            public boolean importData(TransferSupport support) {
              try {
                List<BufferedImage> images = new ArrayList<BufferedImage>();
                for (URI u : getURIs(support)) {
                  try {
                    images.add(ImageIO.read(u.toURL()));
                  } catch (IOException e) {
                  }
                }
                addExamples(images);
                return true;
              } catch (IOException e) {
                return false;
              } catch (UnsupportedFlavorException e) {
                return false;
              } catch (URISyntaxException e) {
                return false;
              }
            }
          });
      list.setCellRenderer(
          new DefaultListCellRenderer() {
            @Override
            public Component getListCellRendererComponent(
                JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
              super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);

              Example example = (Example) value;

              setHorizontalAlignment(SwingConstants.CENTER);
              setText(null);
              setIcon(example.getIcon());
              setBorder(BorderFactory.createEmptyBorder());

              return this;
            }
          });
      JScrollPane jsp = new JScrollPane(list);
      jsp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
      jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

      final JButton remove = new JButton("Remove");
      remove.addActionListener(
          new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
              int[] indices = list.getSelectedIndices();
              for (int i = indices.length - 1; i >= 0; i--) {
                model.remove(indices[i]);
              }
            }
          });
      list.addListSelectionListener(
          new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
              remove.setEnabled(list.getSelectedIndex() != -1);
            }
          });
      remove.setEnabled(false);

      panel = new JPanel(new GridBagLayout());
      // Add list
      GridBagConstraints c = new GridBagConstraints();
      c.gridx = 0;
      c.gridy = 0;
      c.weightx = 1;
      c.weighty = 1;
      c.fill = GridBagConstraints.BOTH;
      panel.add(jsp, c);
      // Add remove button
      c = new GridBagConstraints();
      c.gridx = 0;
      c.anchor = GridBagConstraints.WEST;
      panel.add(remove, c);
    }