wp_dropdown_categories broken?

Hello!

I use this code to create a category dropdown box:

<form action="<?php bloginfo('url'); ?>" method="get">
	<div>
		<?php _e('plz choose:'); ?><br />
		<?php wp_dropdown_categories('child_of=14&orderby=name&show_count=0&hierarchical=1&hide_empty=1'); ?>
			<input type="submit" name="submit" value="&raquo;" />
	</div>
	</form>

And, fair enough, when I choose a category I get the posts of the chosen category displayed. But technically I don’t seem to be on a category page since this code doesn’t give me the correct category feed:

<?php $cat=the_category_ID ; ?>
<li>
<?php echo '<a href="'.get_category_feed_link($cat, 'atom').'">RSS-Feed dieser Auswahl</a>'; ?>
</li>

The above gives me “mydomain/categories/subcategory/?submit=»“
instead of “mydomain/categories/subcategory/atom“!

Why? What’s wrong? ANd why does the browser show this “?submit=»”
at the end of the pretty permalink? Can I get rid of this behaviour?

thx,
piedro