is_tree problem

Hey all,

I’m having some trouble getting the is_tree() function to work. I’ve set it up as the codex, and other pages, state, but the values which it to me are always from the else statement of my if argument, regardless of which page i go to.

I’m running my wp installation on a subdirectory of my localhost, could that be a problem?

Here’s what I’ve put into my functions.php:

<?php

function is_tree($pid) {      // $pid = The ID of the page we're looking for pages underneath
	global $post;         // load details about this page
	if(is_page()&&($post->post_parent==$pid||is_page($pid)))
               return true;   // we're at the page or at a sub page
	else
               return false;  // we're elsewhere
}

?>

<?php

if (is_tree("374")) { // if root page is the products page (change id as appropriate)

	$selection = 'selection_products';
	$logoimg = 'images/site/products_logo.gif';

} elseif (is_tree("148")) { // if root page is the shop section

	$selection = 'selection_shop';
	$logoimg = 'images/site/shop_logo.gif';	

} elseif (is_tree("382")) { // if root page is the help section

	$selection = 'selection_help';
	$logoimg = 'images/site/help_logo.gif';	

} else {

	$selection = 'selection_home';
	$logoimg = 'images/site/home_logo.gif';	

}

?>

All help appreciated!

nb:
When I get this working I want to make the modification suggested by Marty Tomly so that grandchildren are also selected, but that’s not an issue for now.