title: NullPointerException when calling Window.setVisible()
body: <p>I have a heavy GUI application. Every time I start it, I get the following stack trace from the EventDispatchThread:</p>
  
  <pre><code>14:30:04:115 &gt;&gt; java.lang.NullPointerException
      at com.mercury.ftjadin.support.jfc11.cs.JTableCS$CellEditorListenerRegistrar.addListener(JTableCS.java:151)
      at com.mercury.ftjadin.infra.abstr.ObjectCS.registerListeners(ObjectCS.java:2736)
      at com.mercury.ftjadin.infra.DefaultCustomClassManager.onCreate(DefaultCustomClassManager.java:575)
      at com.mercury.ftjadin.hooks.WToolkitHook.onCreate(WToolkitHook.java:23)
      at java.awt.Toolkit.createComponent(Toolkit.java)
      at java.awt.Component.addNotify(Component.java:6650)
      at java.awt.Container.addNotify(Container.java:2565)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at javax.swing.JTable.addNotify(JTable.java:683)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at java.awt.Container.addNotify(Container.java:2576)
      at javax.swing.JComponent.addNotify(JComponent.java:4693)
      at javax.swing.JRootPane.addNotify(JRootPane.java:738)
      at java.awt.Container.addNotify(Container.java:2576)
      at java.awt.Window.addNotify(Window.java:664)
      at java.awt.Frame.addNotify(Frame.java:470)
      at java.awt.Window.show(Window.java:860)
      at java.awt.Component.show(Component.java:1591)
      at java.awt.Component.setVisible(Component.java:1543)
      at java.awt.Window.setVisible(Window.java:843)
      at ... my_classes_stack_trace
  </code></pre>
  
  <p>I tried to debug it in java's source to find what I did wrong and what required object is <code>null</code>, but I got stuck since I don't have the source for <code>com.mercury.ftjadin</code> package...</p>
  
  <p>BTW, the application runs OK regardless this exception, but I would like to resolve this anyway..</p>
  
  <p>Is anyone familiar with this problem? </p>