code: @Override
  	protected void appendOptionHtml(final AppendingStringBuffer buffer, final T choice,
  		final int index, final String selected)
  	{
  
  		final T currentOptGroup = choice;
  		if (isNewGroup(currentOptGroup))
  		{
  			if (!isFirst(index))
  			{
  				buffer.append(CLOSE_OPTGROUP_TAG);
  			}
  			appendOptGroupLabel(buffer, currentOptGroup);
  		}
  
  		super.appendOptionHtml(buffer, choice, index, selected);
  
  		if (isLast(index))
  		{
  			buffer.append(CLOSE_OPTGROUP_TAG);
  		}
  		last = currentOptGroup;
  
  	}
docs: {@inheritDoc}