Conflict with wp_dropdown_categories()

Hi,

I have difficulties sorting wordpress tags with the plugin.
In my custom post Taxonomy Order panel, I am able to sort all my custom taxonomies except the wordpress native tags.
If I try to force the order by name on my wp_dropdown_categories(), nothing happen and the BO natural order of the tag is applied.

<?php wp_dropdown_categories( array( 'taxonomy' => 'post_tag', 'hide_empty' => false, 'show_option_all' => 'Tous les métiers', 'name' => 'met_projet' ,'selected' => $chosen_tag, 'orderby' => 'name') ); ?>

If I remove the plugin, the ‘orderby’ property works fine.

Do I do something wrong? Does the plugin handle wp_dropdown_categories() function or tags?

Thanks!