edit_form.php

<?php

class block_course_overview_uwmoodle_edit_form extends block_edit_form {

    protected function specific_definition($mform) {

        // Section header title according to language file.
        $mform->addElement('header', 'configheader', get_string('blocksettings', 'block'));

        $mform->addElement('advcheckbox', 'config_combineongoing', get_string('combineongoing', 'block_course_overview_uwmoodle'), null, null, array(0, 1));
        $mform->setDefault('config_nontermseparate', 0);
    }
}