code: protected WebMarkupContainer newTabsContainer(final String id)
  	{
  		final WebMarkupContainer wmc = new WebMarkupContainer(id)
  		{
  			/** The Constant serialVersionUID. */
  			private static final long serialVersionUID = 1L;
  
  			/**
  			 * {@inheritDoc}
  			 */
  			@Override
  			protected void onComponentTag(final ComponentTag tag)
  			{
  				super.onComponentTag(tag);
  				tag.put("class", getTabContainerCssClass());
  			}
  		};
  		wmc.setOutputMarkupId(true);
  		return wmc;
  	}
docs: Generates the container for all tabs. The default container automatically adds the css
  <code>class</code> attribute based on the return value of {@link #getTabContainerCssClass()}
  
  @param id
  container id
  @return container