/**
  * This function builds an 'select course' form in the add category process,
  * if parent id is 0, it will only show courses
  */
 protected function build_select_course_form()
 {
     $select = $this->addElement('select', 'select_course', array(get_lang('PickACourse'), 'test'), null);
     $coursecat = Category::get_all_courses(api_get_user_id());
     //only return courses that are not yet created by the teacher
     foreach ($coursecat as $row) {
         $select->addoption($row[1], $row[0]);
     }
     $this->setDefaults(array('hid_user_id' => $this->category_object->get_user_id(), 'hid_parent_id' => $this->category_object->get_parent_id()));
     $this->addElement('hidden', 'hid_user_id');
     $this->addElement('hidden', 'hid_parent_id');
     $this->addElement('submit', null, get_lang('Ok'));
 }