is_page conditional not work in sidebar.php

Hi man,
i made some pages, in this page i would like show only some post.
Then i insert this code in page.php

<?php } elseif ( is_page('page name') ) { ?>
	<?php
$query= 'cat=38&orderby=date&order=ASC';
query_posts($query);
?>
<?php while ( have_posts() ) : the_post() ?>
	<?php if (in_category('30,31,32,37,1,34,33,36,29,2,7,23,9,5,11,18,16,22,20,15,21,25,6,26,19,17,14,24,13,12,10,27,28,8'))continue; ?>

at end of while i insert

<?php $wp_query->is_page = true; ?>

and it’s works very well.
Now when i change the sidebar.php for show the categories for this page, the conditional elseif do not work never!

<?php } elseif ( is_page('page name') ) { ?>
			<li id="categories">
				<h3><?php _e('Name tab', 'sandbox'); ?></h3>

<ul>
				<?php wp_list_cats('sort_column=name&hierarchical=1&exclude=1,30,33,34,36,29,2,8') ?>
				</ul>
			<?php } else {
// this works ever
?>

Have you some suggest?
This’s a WP bug?

thanks

ps. i’m apologies for my english.