init action in index.php: may be serialised in $_POST['s'] and not passed in $_POST['action']
open_label() -> label_element() (for consistency with *_element(), easy insertion in open_td()
dropdown_element(): do class merging right
use list api, css-table api in many places
fix sus/css.rphp: include global css
css: add !important to make direct class specification override derived rules
fix broken scroll position restoration