private function loadForm()
{
// get group values for dropdown
$ddmValues = BackendProfilesModel::getGroupsForDropDown($this->profileId, $this->id);
// create form
$this->frm = new BackendForm('editProfileGroup');
// create elements
$this->frm->addDropdown('group', $ddmValues, $this->profileGroup['group_id']);
$this->frm->addDate('expiration_date', $this->profileGroup['expires_on']);
$this->frm->addTime('expiration_time', $this->profileGroup['expires_on'] !== null ? date('H:i', $this->profileGroup['expires_on']) : '');
// set default element
$this->frm->getField('group')->setDefaultElement('');
}