Sidebar Dropdown Catagorie Selector

Hello,

I am having a small issue with my wordpress blog. I have added in a drop down menu in the sidebar so that people can select which catagoriy they want to go to. The problem is that only on my home page the drop-down box is already preselected on a catagories. If I go to a page such as “about” then it works properly say “Select a category”.

I have pasted the code that i am using below. Can you tell me what to do to fix this problem? Thanks!

<div class="widgetarea">
<h2>Categories</h2>
<form action="<?php bloginfo('url'); ?>/" method="get">

<?php
	$select = wp_dropdown_categories('show_option_none=Select a catagory&orderby=name&show_count=1&hierarchical=1&echo=0');
	$select = preg_replace("#<select([^>]*)>#", "<select$1 onchange='return this.form.submit()'>", $select);
	echo $select;
?>
	<noscript><input type="submit" value="View" /></noscript>
	</form>
</div>