reset wp_dropdown_categories ?

Has anyone run across the issue where wp_dropdown_categories seems to need to be reset or refreshed in order to list categories by the arguments orderby=name&order=ASC rather than ordering categories starting with the name of the category page?

I am using:

<form action="<?php bloginfo('url'); ?>" method="get"><?php wp_dropdown_categories('orderby=name&order=ASC'); ?><input type="submit" name="submit" value="Go" /></form>

in sidebars on both single and category pages, and while the category list on a single page is alphabetical, the category list on a category page shows that category as the selection, not the first in alphabetical order.

Any ideas? Thanks