Add a button into change schema-privileges page for check all checkbox

Hi,
when i go into the change schema-privileges page:
http://localhost/chive/#privileges/users/Ymdfd3AJQ==/schemata

and i select a schema name for apply the privileges, i think that's good to have a button for select/deselect all checkbox at once so i don't click on every checkbox when i need to give all privileges for that database.
Thank you.