First thing we need to do is create a thematic child theme. This way we won’t make direct changes to Thematic.

The search box will be displayed on the right of the menu, inside of the #access div. The way Thematic hooks and actions were constructed will first need to remove the thematic_access() action from the thematic_header() hook. If all this sounds a bit difficult fear not. All you have to do is add this code inside of functions.php file of your child theme (don’t forget the <?php opening tag and the ?> ending tag).

// Remove default Thematic actions
function remove_thematic_actions() {
    remove_action('thematic_header','thematic_access',9);
}
add_action('init','remove_thematic_actions');

If everything is working properly when you reload your WordPress installation the entire menu would have disappear! Now we can create our own menu WITH the search box on the right of it! Add this code at the end of your functions.php:

// Create a custom access div with the menu and search box
function search_access() { ?>
    	<div id="access">
    		<div class="skip-link"><a href="#content" title="<?php _e('Skip navigation to the content', 'thematic'); ?>"><?php _e('Skip to content', 'thematic'); ?></a></div>
            <?php wp_page_menu('sort_column=menu_order') ?>

			<div id="access-search">
				<form id="searchform" method="get" action="<?php bloginfo('home') ?>">
					<div>
						<input id="s" name="s" type="text" value="<?php echo wp_specialchars(stripslashes($_GET['s']), true) ?>" size="20" tabindex="1" />
						<input id="searchsubmit" name="searchsubmit" type="submit" value="<?php _e('Search', 'thematic') ?>" tabindex="2" />
					</div>
				</form>
			</div>

        </div><!-- #access -->
<?php }
add_action('thematic_header','search_access',9);

Reload your page and the search box will be there, but not where you expected it to be! We’ll need to add a bit of css styling to it.

Go ahead and open the style.css and at the end of it add this css code:

#access-search{
	position:absolute;
	left:50%;
	width:260px;
	margin-left:170px;
	height:29px;
	border-top:1px solid #ccc;
	border-left:1px solid #ccc;
	border-right:1px solid #ccc;
	padding:2px 0 0 4px;
}

This is it! You now have successfully added a search box to the right of your thematic main menu!

Related posts:

1. Replacing the Thematic Menu with a DropDown List of Categories
2. Green anyone? Try Commune – Thematic Child Theme!
3. Byty the Free Child Theme – Built on Thematic