public function removeSortable($element)
    {
        if (array_has($this->sortable, $element)) {
            return $this->sortable = array_except($this->sortable, $element);
        }

        if (in_array($element, $this->sortable(), true)) {
            return $this->sortable = array_except(
                $this->sortable,
                array_search($element, $this->sortable, true)
            );
        }

        return $this->sortable;
    }