[Plugin: NextGEN Gallery] Remove Twitter and Facebook links

Hi,

I want to delete the Twitter and Facebook links in the administration screens of the plugin NextGEN Gallery.
I added in my theme fonctions.php file the following lines to disable the “/nextgen-gallery/admin/css/ngg_social_media.css” file:

function remove_plugin_javascript() {
	wp_deregister_script('ngg_social_media');
}
add_action('wp_print_scripts', 'remove_plugin_javascript', 100);

function remove_plugin_style() {
    wp_deregister_style('ngg_social_media');
}
add_action('wp_print_styles', 'remove_plugin_style', 100);

The function remove_plugin_javascript() is taken into account but the function remove_plugin_style() does not seem to be taken into account.

Can anyone help me?
Many thanks

Best regards