Hi there,
after a couple hours of searches, trials and errors, I found the solution. Here’s the code:
<?php
/* if the current pages has a parent, i.e. we are on a subpage */
if($post->post_parent){
$parent_title = get_the_title($post->post_parent);
//$children = wp_list_pages("title_li=&include=".$post->post_parent."&echo=0"); // list the parent page
$children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0"); // append the list of children pages to the same $children variable
}
/* else if the current page does not have a parent, i.e. this is a top level page */
else {
$parent_title = get_the_title($post->ID);
//$children = wp_list_pages("title_li=&include=".$post->ID."&echo=0");
$children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0"); // form a list of the children of the current page
}
/* if we ended up with any pages from the queries above */
if ($parent_title) { ?>
<h2><?php echo $parent_title; ?></h2>
<?php }
if ($children) { ?>
<ul class="submenu">
<?php echo $children; /*print list of pages*/ ?>
</ul>
<?php } ?>
