title: jButton not clickable in jTable
body: <p>I got the problem, that I cannot click on buttons. They behave like they are just textfields with the design of buttons. </p>
  
  <p>my <code>Main</code>: </p>
  
  <pre><code>    tableModStudents = (DefaultTableModel) studentsTable.getModel();
      studentsTable.getColumn(studentsTable.getColumnName(8))
                   .setCellRenderer(new JButtonRenderer());
      studentsTable.getColumn(studentsTable.getColumnName(8))
                   .setCellEditor(new JButtonEditor());
  </code></pre>
  
  <p>my <code>CellRenderer</code>:</p>
  
  <pre><code>public class JButtonRenderer implements TableCellRenderer {    
      private JButton button = new JButton();
  
      public Component getTableCellRendererComponent(JTable table,
              Object buttonText, boolean isSelected, boolean hasFocus, 
              int row, int column) {
          table.setShowGrid(true);
          button.setText("Details");
          button.setToolTipText(buttonText.toString());
          return button;
      }
  }
  </code></pre>
  
  <p>my <code>CellEditor</code>:</p>
  
  <pre><code>    public class JButtonEditor extends AbstractCellEditor implements TableCellEditor {
  
      private JButton button;
      private String txt;
  
      public JButtonEditor() {
          super();
          button = new JButton();
          button.setOpaque(true);
          button.addActionListener(new ActionListener() {
              public void actionPerformed(ActionEvent ae) {
                  System.out.println("Button gedrückt!");
              }
          });
      }
  
      public Object getCellEditorValue() {
          return null;
      }
  
      public boolean isCellEditable(EventObject anEvent) {
          return true;
      }
  
      public boolean shouldSelectCell(EventObject anEvent) {
          return false;
      }
  
      public boolean stopCellEditing() {
          return super.stopCellEditing();
      }
  
      public void cancelCellEditing() {
      }
  
      public void addCellEditorListener(CellEditorListener l) {
      }
  
      public void removeCellEditorListener(CellEditorListener l) {
      }
  
      public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
          txt = (value == null) ? "" : value.toString();
          button.setText(txt);
          return button;
      }
  }
  </code></pre>
  
  <p>Can you find the issue with that? It drives my crazy... </p>
  
  <p>Thanks so much :)</p>