code: public void removeButton(Widget button) {
  
          m_buttonPanel.remove(button);
          if (m_buttonPanel.getWidgetCount() == 0) {
              m_buttonPanel.setStyleName(I_CmsLayoutBundle.INSTANCE.dialogCss().hideButtonPanel());
          }
      }
docs: Removes the given button widget from the button panel.<p>
  
  @param button the button widget to remove