public function render()
	{
		$legend		= $this->renderInner( $this->legend );
		if( !is_string( $legend ) )
			throw new InvalidArgumentException( 'Fieldset legend is neither rendered nor renderable' );
		
		$content	= $this->renderInner( $this->content );
		if( !is_string( $content ) )
			throw new InvalidArgumentException( 'Fieldset content is neither rendered nor renderable' );

		return UI_HTML_Tag::create( "fieldset", $legend.$content, $this->getAttributes() );
	}