Why the_title() filter is also applied in menu title?

ah, I just knew the answer…

the_title() filter has additional parameter = $id. I can compare the value of $id parameter with $post->ID. Although the title of the page is the same with the title of its corresponding menu, the ID is different. Hence I can differentiate the page title and the menu title and apply the filter accordingly.

For instance (because people require examples.. like myself)

add_filter('the_title','add_field');

function add_field($title)
{
global $id;
if (in_category('1') && $id) {
	global $post;
	$key = "location";
	$data = get_post_meta($post->ID,$key,true);
global $wp_query;
//print_r($wp_query);

	return $title."</a><br /><div style='font-size:10px;line-height:120%;padding-top:3px'>".$data."</div><a>";

    }
else {
	return $title;	

}
}