code: private void showDialog(final AjaxRequestTarget _target,
                              final String _key,
                              final boolean _isSniplett,
                              final boolean _goOnButton)
      {
          final ModalWindowContainer modal = ((AbstractContentPage) getPage()).getModal();
  
          modal.setInitialWidth(350);
          modal.setInitialHeight(200);
  
          modal.setPageCreator(new ModalWindow.PageCreator() {
  
              private static final long serialVersionUID = 1L;
  
              @Override
              public Page createPage()
              {
                  return new DialogPage(((AbstractContentPage) getPage()).getPageReference(),
                                  _key, _isSniplett, _goOnButton);
              }
          });
  
          if (_goOnButton) {
              modal.setWindowClosedCallback(new WindowClosedCallback()
              {
  
                  private static final long serialVersionUID = 1L;
  
                  @Override
                  public void onClose(final AjaxRequestTarget _target)
                  {
                      if (AjaxSubmitCloseButton.this.validated) {
                          _target.appendJavaScript(getExecuteScript());
                      }
                  }
              });
          }
          modal.show(_target);
      }
docs: Shows a modal DialogPage.
  
  @param _target       AjaxRequestTarget to be used for opening the modal
  DialogPage
  @param _key the      Key to get the DBProperties from the eFapsDataBaase or a
  code sniplett
  @param _isSniplett   is the parameter _key a key to a property or a
  sniplett
  @param _goOnButton   should a button to go on be rendered