protected function getDropdownOptions()
    {
        $values = $this->getDropdownValues();
        $labels = $this->getDropdownLabels();

        // Make sure that labels are set for each value
        foreach ($values as $value) {
            if (isset($labels[ $value ])) continue;

            $labels[ $value ] = $value;
        }

        return array_intersect_key($labels, array_flip($values));
    }