private function loadForm()
{
// get group values for dropdown
$ddmValues = BackendProfilesModel::getGroupsForDropDown($this->id);
// create form
$this->frm = new BackendForm('addProfileGroup');
// create elements
$this->frm->addDropdown('group', $ddmValues);
$this->frm->addDate('expiration_date');
$this->frm->addTime('expiration_time', '');
// set default element
$this->frm->getField('group')->setDefaultElement('');
}