Shortcode resolving at top of content

The shortcode for the list is resolving always at the top of the content, this happens because the “favourites-template” is echoing, instead of returning.
I hacked this by moving the template-content into the main php file, but this is not elegant. Maybe the author can fix this bug by returning the template somehow, instead of using echo.

Function simple_print_favourites( $atts ){
	$GLOBALS['simple_favourites_running'] = true;
	extract( shortcode_atts( array(
        'user_id' => false
    ), $atts ) );
	$favourites = simple_favourites::get_favourites($user_id);
	$fav_output = "";
	if(!empty($favourites)) :
		$fav_list = do_shortcode('[products ids="' . implode(',', $favourites) . '" columns="4"]');
		$fav_output = "<div id='simple_favourites_display'><h2>Your Favourites</h2>" . $fav_list . "</div>";
	endif;
	unset($GLOBALS['simple_favourites_running']);
	return $fav_output;
}