Hi,
I've added 3 lines in "change_password_form.php" because I have to insert a checkbox in the page, this is the code:
$mform->addElement('checkbox', 'checkbox', get_string('I accept policy'));
$mform->addRule('checkbox', get_string('required'), 'required', null, 'client');
$mform->setType('checkbox', PARAM_INT);
But on the page the string is printed between four square brackets and I don't know why.