WordPress at a glance
filter is not described

show_network_site_users_add_new_form filter-hook . WP 3.1.0

Filters whether to show the Add New User form on the Multisite Users screen.

Usage

add_filter( 'show_network_site_users_add_new_form', 'filter_function_name_1350' );
function filter_function_name_1350( $bool ){
	// filter...

	return $bool;
}
$bool(true/false)
Whether to show the Add New User form.
Default: true

Where the hook is called

In file: /wp-admin/network/site-users.php
show_network_site_users_add_new_form
wp-admin/network/site-users.php 322
if ( current_user_can( 'create_users' ) && apply_filters( 'show_network_site_users_add_new_form', true ) ) : ?>

Where the hook is used (in WP core)

Does not used.