En résumé :
form_handler.php uses $_POST
I had to change this to using optional_param() to get this working under 1.9.x
Also in form_handler.php
switch($action){
case "newtarget":
switch($submit){
case "Cancel":
...
case "Save changes":
Doesn't work if get_string('savechanges'). != 'Save changes' which
is likely for lang != en